Messages won't deliver JPEGs in Tahoe 26.2

My Mac Studio (M1 chip) running Tahoe 26.2 will not send JPEG files in Messages, regardless of recipient type (iMessage or SMS). This took place right after I upgraded from Ventura. Rebooting and restarting has no effect on this. I saw on here that someone else has a similar problem which they solved by converting JPEG files to HEIC, but I don't want to have to do that conversion all the time. Has anyone else had this issue and what did they do to fix it?