Can confirm that there is some sort of an issue with image uploading. Here's how I encountered it:
1. Add a new cache.
2. Add a reviewer note.
3. Attempt to add images (either by dropping photos or by selecting)
They always end up saying "Upload Failed". In the developer console I can see that the server is returning a 400 response (bad request). Here's the full server response:
{"statusCode":400,"statusMessage":"Bad Request","errorMessage":"Failed to post draft log image to the image service; BadRequestException","uri":"http://imagesapi.Groundspeak.biz/images/v1/images"}
For some reason I only encountered this issue on desktop using Chrome browser. When I accessed the same page from my phone (also on chrome) I did not encounter the issue.
Seems like a bug to me.