Why are there thousands of Snapshot_xxx files in my /tmp folder?

I'm running Octoprint 1.4.0 on an RPi 3B+ (octopi version 0.15.1). My uptime is 62 days. I just logged into my Pi and noticed that there are over 2,800 "Snapshot" PNG files in my /tmp directory:

-rw------- 1 pi pi 29711 Jul 26 21:22 Snapshot_05556506cfb011ea9309b827eb454a43.png
-rw------- 1 pi pi 25812 Jul 26 21:24 Snapshot_3d6b2f48cfb011eabad6b827eb454a43.png
-rw------- 1 pi pi 24978 Jul 26 21:27 Snapshot_b1986962cfb011eabb0db827eb454a43.png
-rw------- 1 pi pi 24277 Jul 26 21:28 Snapshot_e923dc68cfb011ea9b8ab827eb454a43.png
-rw------- 1 pi pi 25117 Jul 26 21:30 Snapshot_209bbc24cfb111ea93ebb827eb454a43.png
-rw------- 1 pi pi 26916 Jul 26 21:33 Snapshot_93cb17eecfb111ea84c8b827eb454a43.png
-rw------- 1 pi pi 28572 Jul 26 21:35 Snapshot_cc4cb816cfb111eaab7eb827eb454a43.png
-rw------- 1 pi pi 26582 Jul 26 21:36 Snapshot_046d6f9ccfb211ea888cb827eb454a43.png
-rw------- 1 pi pi 27335 Jul 26 21:40 Snapshot_775c8524cfb211eab4c9b827eb454a43.png
-rw------- 1 pi pi 25743 Jul 26 21:41 Snapshot_b077ae4ccfb211eaa27bb827eb454a43.png
-rw------- 1 pi pi 27105 Jul 26 21:43 Snapshot_e8412934cfb211ea8ea3b827eb454a43.png

Does anyone know where these are coming from, and how I can stop them from being created?

2020-07-27 16:32:07,722 - octoprint.startup - INFO - ******************************************************************************
2020-07-27 16:32:07,724 - octoprint.startup - INFO - Starting OctoPrint 1.4.0
2020-07-27 16:32:07,725 - octoprint.startup - INFO - ******************************************************************************
2020-07-27 16:32:07,793 - octoprint.util.connectivity_checker - INFO - Connectivity changed from offline to online
2020-07-27 16:32:07,798 - octoprint.startup - INFO - Blacklist processing done, adding 1 blacklisted plugin versions: roomtemp (any)
2020-07-27 16:32:07,848 - octoprint.plugin.core - INFO - Loading plugins from /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins, /home/pi/.octoprint/plugins and installed plugin packages...
2020-07-27 16:32:10,258 - octoprint.plugin.core - INFO - Plugin Octoslack (2.0.0) is disabled.
2020-07-27 16:32:11,633 - octoprint.plugin.core - INFO - Found 32 plugin(s) providing 31 mixin implementations, 63 hook handlers
2020-07-27 16:32:12,470 - octoprint.server.heartbeat - INFO - Starting server heartbeat, 900.0s interval
2020-07-27 16:32:12,500 - octoprint.server - INFO - Intermediary server started
2020-07-27 16:32:12,501 - octoprint.plugin.core - INFO - Loading plugins from /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins, /home/pi/.octoprint/plugins and installed plugin packages...
2020-07-27 16:32:13,371 - octoprint.plugin.core - INFO - Found 32 plugin(s) providing 31 mixin implementations, 63 hook handlers
2020-07-27 16:32:13,421 - octoprint.filemanager.storage - INFO - Initializing the file metadata for /home/pi/.octoprint/uploads...
2020-07-27 16:32:14,220 - octoprint.filemanager.storage - INFO - ... file metadata for /home/pi/.octoprint/uploads initialized successfully.
2020-07-27 16:32:14,226 - octoprint.server - INFO - Added new permission from plugin action_command_prompt: PLUGIN_ACTION_COMMAND_PROMPT_INTERACT (needs: u"Need(method='role', value=u'plugin_action_command_prompt_interact')")
2020-07-27 16:32:14,227 - octoprint.server - INFO - Added new permission from plugin announcements: PLUGIN_ANNOUNCEMENTS_READ (needs: u"Need(method='role', value=u'plugin_announcements_read')")
2020-07-27 16:32:14,228 - octoprint.server - INFO - Added new permission from plugin announcements: PLUGIN_ANNOUNCEMENTS_MANAGE (needs: u"Need(method='role', value=u'plugin_announcements_manage'), Need(method='role', value=u'plugin_announcements_read')")
2020-07-27 16:32:14,229 - octoprint.server - INFO - Added new permission from plugin appkeys: PLUGIN_APPKEYS_ADMIN (needs: u"Need(method='role', value=u'plugin_appkeys_admin')")
2020-07-27 16:32:14,231 - octoprint.server - INFO - Added new permission from plugin backup: PLUGIN_BACKUP_ACCESS (needs: u"Need(method='role', value=u'plugin_backup_access')")
2020-07-27 16:32:14,233 - octoprint.server - INFO - Added new permission from plugin logging: PLUGIN_LOGGING_MANAGE (needs: u"Need(method='role', value=u'plugin_logging_manage')")
2020-07-27 16:32:14,236 - octoprint.server - INFO - Added new permission from plugin pi_support: PLUGIN_PI_SUPPORT_STATUS (needs: u"Need(method='role', value=u'plugin_pi_support_check')")
2020-07-27 16:32:14,236 - octoprint.server - INFO - Added new permission from plugin pluginmanager: PLUGIN_PLUGINMANAGER_MANAGE (needs: u"Need(method='role', value=u'plugin_pluginmanager_manage')")
2020-07-27 16:32:14,238 - octoprint.server - INFO - Added new permission from plugin pluginmanager: PLUGIN_PLUGINMANAGER_INSTALL (needs: u"Need(method='role', value=u'plugin_pluginmanager_install'), Need(method='role', value=u'plugin_pluginmanager_manage')")
2020-07-27 16:32:14,240 - octoprint.server - INFO - Added new permission from plugin printer_safety_check: PLUGIN_PRINTER_SAFETY_CHECK_DISPLAY (needs: u"Need(method='role', value=u'plugin_printer_safety_check_display')")
2020-07-27 16:32:14,242 - octoprint.server - INFO - Added new permission from plugin softwareupdate: PLUGIN_SOFTWAREUPDATE_CHECK (needs: u"Need(method='role', value=u'plugin_softwareupdate_check')")
2020-07-27 16:32:14,244 - octoprint.server - INFO - Added new permission from plugin softwareupdate: PLUGIN_SOFTWAREUPDATE_UPDATE (needs: u"Need(method='role', value=u'plugin_softwareupdate_update')")
2020-07-27 16:32:14,260 - octoprint.printer.standard - INFO - Using print time estimator provided by PrintTimeGenius
2020-07-27 16:32:14,659 - octoprint.plugins.softwareupdate - INFO - Loaded version cache from disk
2020-07-27 16:32:16,973 - octoprint.util.pip - INFO - Using "/home/pi/oprint/bin/python2 -m pip" as command to invoke pip
2020-07-27 16:32:19,173 - octoprint.util.pip - INFO - Version of pip is 9.0.3
2020-07-27 16:32:19,174 - octoprint.util.pip - INFO - pip installs to /home/pi/oprint/lib/python2.7/site-packages (writable -> yes), --user flag needed -> no, virtual env -> yes
2020-07-27 16:32:19,176 - octoprint.util.pip - INFO - ==> pip ok -> yes
2020-07-27 16:32:19,181 - octoprint.plugin.core - INFO - Initialized 31 plugin implementation(s)
2020-07-27 16:32:19,232 - octoprint.plugin.core - INFO - 32 plugin(s) registered with the system:
|  Access Anywhere - The Spaghetti Detective (1.3.2) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_thespaghettidetective
|  Action Command Prompt Support (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/action_command_prompt
|  Announcement Plugin (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/announcements
|  Anonymous Usage Tracking (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/tracking
|  Application Keys Plugin (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/appkeys
|  Backup & Restore (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/backup
|  Bed Visualizer (0.1.14) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_bedlevelvisualizer
|  Core Wizard (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/corewizard
|  Discovery (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/discovery
|  Enclosure Plugin (4.12) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_enclosure
|  Error Tracking (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/errortracking
|  Filament Manager (0.5.3) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_filamentmanager
|  FileManager (0.1.4) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_filemanager
|  Firmware Updater (1.7.0) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_firmwareupdater
|  Fullscreen Plugin (0.0.5) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_fullscreen
|  Logging (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/logging
|  Login UI (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/loginui
|  MultiCam (0.2.8) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_multicam
|  Navbar Temperature Plugin (0.14) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_navbartemp
| !Octoslack (2.0.0) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_Octoslack
|  Pi Support Plugin (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/pi_support
|  Plugin Manager (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/pluginmanager
|  Printer Safety Check (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/printer_safety_check
|  Printoid Plugin (1.0.2) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_printoid
|  PrintTimeGenius Plugin (2.2.5) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_PrintTimeGenius
|  Prusa Leveling Guide (1.0.8) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_PrusaLevelingGuide
|  PrusaSlicer Thumbnails (0.1.2) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_prusaslicerthumbnails
|  Python 3 Check (0.1.4) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_python3plugincompatibilitycheck
|  Software Update (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/softwareupdate
|  TouchUI (0.3.14) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_touchui
|  TP-Link Smartplug (0.9.23) = /home/pi/oprint/local/lib/python2.7/site-packages/octoprint_tplinksmartplug
|  Virtual Printer (bundled) = /home/pi/oprint/lib/python2.7/site-packages/octoprint/plugins/virtual_printer
Prefix legend: ! = disabled, # = blacklisted, * = incompatible
2020-07-27 16:32:19,254 - octoprint.environment - INFO - Detected environment is Python 2.7.13 under Linux (linux2). Details:
|  hardware:
|      cores: 4
|      freq: 1400.0
|      ram: 918192128
|  os:
|      id: linux
|      platform: linux2
|  plugins:
|      pi_support:
|          model: Raspberry Pi 3 Model B Plus Rev 1.3
|          octopi_version: 0.15.1
|  python:
|      pip: 9.0.3
|      version: 2.7.13
|      virtualenv: /home/pi/oprint
2020-07-27 16:32:19,274 - octoprint.server - INFO - Reset webasset folder /home/pi/.octoprint/generated/webassets...
2020-07-27 16:32:19,306 - octoprint.server - INFO - Reset webasset folder /home/pi/.octoprint/generated/.webassets-cache...
2020-07-27 16:32:21,053 - octoprint.server - INFO - Shutting down intermediary server...
2020-07-27 16:32:21,056 - octoprint.server - INFO - Intermediary server shut down
2020-07-27 16:32:21,060 - octoprint.events - INFO - Processing startup event, this is our first event
2020-07-27 16:32:21,064 - octoprint.events - INFO - Adding 1 events to queue that were held back before startup event
2020-07-27 16:32:21,071 - octoprint.filemanager - INFO - Adding backlog items from all storage types to analysis queue...
2020-07-27 16:32:21,128 - octoprint.filemanager - INFO - Added 0 items from storage type "local" to analysis queue
2020-07-27 16:32:21,126 - octoprint.plugins.pluginmanager - INFO - Loaded plugin repository data from disk, was still valid
2020-07-27 16:32:21,129 - octoprint.server.util.watchdog - INFO - Running initial scan on watched folder...
2020-07-27 16:32:21,236 - octoprint.server.util.watchdog - INFO - ... initial scan done.
2020-07-27 16:32:21,269 - octoprint.plugins.discovery - INFO - Registered 'OctoPrint instance "MK3s"' for _http._tcp
2020-07-27 16:32:21,363 - octoprint.plugins.discovery - INFO - Registered 'OctoPrint instance "MK3s"' for _octoprint._tcp
2020-07-27 16:32:21,673 - octoprint.plugins.discovery - INFO - Registered OctoPrint instance "MK3s" for SSDP
2020-07-27 16:32:23,180 - octoprint.plugins.pluginmanager - INFO - Loaded notice data from disk, was still valid
2020-07-27 16:32:23,236 - octoprint.server - INFO - Listening on http://127.0.0.1:5000
2020-07-27 16:32:23,403 - octoprint.plugins.pluginmanager - INFO - Loaded plugin repository data from disk, was still valid
2020-07-27 16:32:25,503 - octoprint.plugins.pluginmanager - INFO - Loaded notice data from disk, was still valid
2020-07-27 16:32:25,865 - octoprint.util.pip - INFO - Using "/home/pi/oprint/bin/python2 -m pip" as command to invoke pip
2020-07-27 16:32:25,867 - octoprint.util.pip - INFO - pip installs to /home/pi/oprint/lib/python2.7/site-packages (writable -> yes), --user flag needed -> no, virtual env -> yes
2020-07-27 16:32:25,868 - octoprint.util.pip - INFO - ==> pip ok -> yes
2020-07-27 16:32:25,935 - octoprint.plugins.bedlevelvisualizer - INFO - OctoPrint-BedLevelVisualizer loaded!
2020-07-27 16:32:25,973 - octoprint.plugins.multicam - INFO - MultiCam Loaded! (more: [{'isButtonEnabled': False, 'name': 'Nozzle', 'URL': '/webcam/?action=stream', 'streamRatio': '16:9', 'flipV': False, 'snapshot': 'http://127.0.0.1/webcam/?action=snapshot', 'flipH': False, 'rotate90': False}, {'isButtonEnabled': True, 'name': 'Overhead', 'URL': 'http://192.168.1.5:8081/?action=stream', 'streamRatio': '16:9', 'flipV': False, 'snapshot': 'http://127.0.0.1:8081/?action=snapshot', 'flipH': False, 'rotate90': False}, {'isButtonEnabled': True, 'name': 'Filament', 'URL': 'http://192.168.1.38:8080/video', 'streamRatio': '16:9', 'flipV': False, 'snapshot': 'http://127.0.0.1:8081/?action=snapshot', 'flipH': False, 'rotate90': False}])
2020-07-27 16:32:25,985 - octoprint.plugins.printoid - INFO - Printoid loaded!
2020-07-27 16:32:26,010 - octoprint.plugins.tplinksmartplug - INFO - TPLinkSmartplug loaded!
2020-07-27 16:32:27,054 - octoprint.server.util.sockjs - INFO - New connection from client: ::ffff:192.168.1.4
2020-07-27 16:32:27,374 - octoprint.server.preemptive_cache - INFO - Preemptively caching / (ui _default) for {'query_string': 'l10n=en', 'path': '/', 'base_url': 'http://octopi.local/'}
2020-07-27 16:32:27,448 - octoprint.server.util.flask - INFO - Passively logging in user _admin from ::ffff:192.168.1.4
2020-07-27 16:32:27,452 - octoprint.access.users - INFO - Logged in user: _admin
2020-07-27 16:32:27,505 - octoprint.server.util.sockjs - INFO - User _admin logged in on the socket from client ::ffff:192.168.1.4
2020-07-27 16:32:27,549 - octoprint.plugins.thespaghettidetective - INFO - User account: {u'is_pro': False}
2020-07-27 16:32:34,067 - octoprint.server.util.sockjs - INFO - Client connection closed: ::ffff:192.168.1.4
2020-07-27 16:32:34,196 - octoprint.server.util.sockjs - INFO - New connection from client: ::ffff:192.168.1.4
2020-07-27 16:32:34,544 - octoprint.server.util.flask - INFO - Passively logging in user _admin from ::ffff:192.168.1.4
2020-07-27 16:32:34,547 - octoprint.access.users - INFO - Logged in user: _admin
2020-07-27 16:32:34,587 - octoprint.server.util.sockjs - INFO - User _admin logged in on the socket from client ::ffff:192.168.1.4
2020-07-27 16:32:46,372 - octoprint.server.preemptive_cache - INFO - ... done in 19.00s
2020-07-27 16:32:46,374 - octoprint.server.preemptive_cache - INFO - Preemptively caching / (ui _default) for {'query_string': 'l10n=en', 'path': '/', 'base_url': 'http://192.168.1.5/'}
2020-07-27 16:32:52,898 - octoprint.server.preemptive_cache - INFO - ... done in 6.52s
2020-07-27 16:36:55,641 - octoprint.server.util.sockjs - INFO - Client connection closed: ::ffff:192.168.1.4

Do you have octolapse installed? If so, disable it

I do not have Octolapse installed. "Timelapse Recordings" is also disabled.

Doesn't OctoSlack send snapshots to slack? It could also be the Spaghetti Detective not cleaning up after itself when sending snapshots to be analyzed.

To add some info to that, there's nothing in OctoPrint core that will save image files into the tmp folder, so that must be the doing of some third party plugin.