in CC, under Options, Advanced, do you have a tick in the "only delete files older than 24 hours" fields?
these are the Snag It entries currently used by CC, see if they match up and cover the folder your recent captures reside in.
[snagit 9]
ID=2237
LangSecRef=3024
Detect=HKCU\Software\TechSmith\SnagIt\9
Default=True
RegKey1=HKCU\Software\TechSmith\SnagIt\9\Recent Captures
RegKey2=HKCU\Software\TechSmith\SnagIt\9\SnagItEditor\Recent File List
FileKey1=%LocalAppData%\TechSmith\SnagIt|Tray.bin
[snagit 10]
ID=2238
LangSecRef=3024
Detect=HKCU\Software\TechSmith\SnagIt\10
Default=True
RegKey1=HKCU\Software\TechSmith\SnagIt\10\Recent Captures
RegKey2=HKCU\Software\TechSmith\SnagIt\10\SnagItEditor\Recent File List
FileKey1=%LocalAppData%\TechSmith\SnagIt|Tray.bin
FileKey2=%LocalAppData%\TechSmith\SnagIt\DataStore\AppIcons|.
FileKey3=%LocalAppData%\TechSmith\SnagIt\DataStore\WebSiteIcons|.
FileKey4=%LocalAppData%\TechSmith\SnagIt\Thumbnails|.
[snagit 11]
ID=2293
LangSecRef=3024
Detect=HKCU\Software\TechSmith\SnagIt\11
Default=True
RegKey1=HKCU\Software\TechSmith\SnagIt\11\Recent Captures
RegKey2=HKCU\Software\TechSmith\SnagIt\11\SnagItEditor\Recent File List
FileKey1=%LocalAppData%\TechSmith\SnagIt|Tray.bin
FileKey2=%LocalAppData%\TechSmith\SnagIt\DataStore\AppIcons|.
FileKey3=%LocalAppData%\TechSmith\SnagIt\DataStore\WebSiteIcons|.
FileKey4=%LocalAppData%\TechSmith\SnagIt\Thumbnails|.
[snagit 12]
ID=2391
LangSecRef=3024
Detect=HKCU\Software\TechSmith\SnagIt\12
Default=True
RegKey1=HKCU\Software\TechSmith\SnagIt\12\Recent Captures
RegKey2=HKCU\Software\TechSmith\SnagIt\12\SnagItEditor\Recent File List
FileKey1=%LocalAppData%\TechSmith\SnagIt|Tray.bin
FileKey2=%LocalAppData%\TechSmith\SnagIt\DataStore\AppIcons|*.ico
FileKey3=%LocalAppData%\TechSmith\SnagIt\DataStore\WebSiteIcons|*.ico
FileKey4=%LocalAppData%\TechSmith\SnagIt\Thumbnails|.