At the the risk of adding to the confusion here, TM-Img is now storing files as .jpeg rather than .jpg . I noticed it the other day when I uploaded some images and I have just tested it again with two random pictures (one of my trip to Salisbury last week and an example of my recent attempt at cooking.) These both have .jpg extensions on my Windows 11 laptop but TM-img has changed them to .jpeg.
I know this didn't use to happen, something must have changed at the TM-Img end.
However, I don't believe it matters. The .jpeg problem is a bug in this site's gallery forums, but only there. Pictures hosted elsewhere are just image files and are rendered properly by HTML.
As for avatar the size, I wasn't aware that larger images were accepted. Nonetheless I would recommend you resize to 100x100. Downloading a file that is 1000 times larger than needed is a waste of bandwidth, at the server end as well as each viewer.
Unfortunately it does matter Ian, hence why this thread was started by 1854sailor as his .jpeg file was not accepted as a valid avatar link - the valid examples include only .jpg. I tried a .jpeg extension image myself and received the same Improper.... message.
Regarding file size I agree in essence excepting that 100 x 100 px or less can give a fuzzy avatar. I also like to zoom in to avatars to see the car or maybe another aspect of same. Maybe Simon could offer us a self imposed limit, but well above 100 x 100.
BTW I have no issues using
Imgur as my free picture hosting site.