I have already tried messing with the auto screenshot to make it "smaller" not that I know how besides cropping the image (which did reduce it's file size) but it has solved nothing.
I have the original auto-screenshot still saved.
Trying to upload the map I get this error message: "Thumbnail size invalid: 773745".
I do not touch game files and this mission was no different. Only touched after getting that error message.
It would be really helpful if you would consider attaching the log file and the save.cw4 files to a problem report that you expect assistance with. Saves guesswork.
I was expecting more of an insight as the problem is very simple and seemingly straight forward considering I basically may of got an error code but here you go.
I also included the prev.log just in case.
You can try the upload again. The server has a size limit on the number of bytes in the thumbnail image. That was just a tad too low for this particular thumbnail. I've raised the limit so the upload should go through
Switched back to the auto-generated thumbnail, went to upload and it all went smoothly.