I’ve tried to post images like 5 times and only once was it actually successfull. On my pc it gives a lot of error messages too without really clarifying what format the upload should be. Is there a suggested method (like uploading to imgur first and linking that url) or something?
There are a lot of rough edges with error reporting in lemmy, anything that you can do that can fail doesn’t always tells you why.
In this case, yeah, it’ll be better to post a link of the image hosted in another service, this way you also help the lemmy servers to not fill their disk so quickly.