Trying to upload a picture from https://www.pixiv.net/en/artworks/94242449, and it gives me a screen with the following text all the times I've tried:
error: MediaAsset::Error - Upload failed, try again (upload was stuck in 'processing' state)
Thus I tried to upload the picture downloading it first instead of just giving the source. Instead, it gave a screen with the following information:
Error
Validation failed: Md5 confirmation doesn't match Md5
Details
ActiveRecord::RecordInvalid exception raised
app/logical/upload_service.rb:37:in `start!'
app/controllers/uploads_controller.rb:55:in `create'
Not sure if it's a problem with Pixiv or with Danbooru or with just the picture, but I find it weird and worth reporting, as I don't know if I'm the only user with this problem or there might be more.
By the way, it seems that it only happens to me with this particular picture, as I uploaded later another one (post #4932596), and I had no problems in the upload.