Bug: cannot upload screenshots

[Efreak]

On trying to upload a screenshot in an issue, I get a red toast stating "failed to load image". In #54 I added screenshots by uploading them to a gist (my usual workaround for uploading files on Android).

Video here. (Both are the same)

Note that if I embed a video as an image (I'm doing so below) on the github website it will show as a text link; in fasthub it's just missing entirely, with no indication it exists. Oddly, it does show a first-frame preview while submitting.