4Bakers
3.8.1
if you rename the image you assign to be uploaded as a thumbnail, you CANNOT edit any of the world details (including selecting a replacement image) until the SDK finds the missing image again. you MUST make a new file with the exact name/path as the missing file in order to recover this state.
steps to reproduce:
  1. assign image to be uploaded as thumbnail
  2. rename or remove image file
  3. attempt to change world details (including assigning a new thumbnail)
bugged result: cannot change any world details (including assigning a new thumbnail)
expected result: should be able to assign new thumbnail
  1. restore image file
  2. attempt to change world details (including assigning a new thumbnail)
extra details: in my 1/only test (when I encountered it wild) I had not yet made my first build (no Blueprint ID assigned yet). this may or may not be the only case in which this bug occurs.