Django/Wagtail some images upload error 500

Question

Am using Wagtail (Django variant CMS) in virtualenv, on FastCGI + Apache + shared hosting.

When uploading images via the built-in Wagtail Image Uploader, certain images work and compile correctly whilst certain uploads cause a 500 Internal Server Error.

Have tried looking for a pattern in types of images that cause the Error but can't spot any similarities.

I am able to upload various JPGs, GIFs, PNGs, sizes varied from 88KB to 236KB, largest dimensions are 1000px x 950px

The files causing errors are also variety of JPGs, GIFs, PNGs. I cannot upload anything bigger than 300KB, although some files that are only 100KB or less also cause 500 error. Uploading via django-admin causes the same issues.

The images work when I upload through sftp and cpanel so there's no problem there.

Wagtail uses Pillow for image handling.

I'm not sure where to begin looking for this. Is it a Pillow or Django error?

Answer 1

I'd suspect your web server is setting a limit on request sizes - we've encountered similar things when deploying on nginx, which imposes a 1 Mb limit on requests out-of-the-box. (For nginx, the relevant setting is client_max_body_size.) If you're seeing a plain 500 Internal Server Error page rather than a Django error, that does suggest that the error is happening at the web server level rather than within Django... you'll hopefully get a more informative error message if you check the web server's error log.

One easy check you can try is to upload the same files in Wagtail's 'Documents' area - this doesn't do any kind of processing on the files (it only stores them), so if the uploads are still failing there, that eliminates Pillow from the possibilities.

Answer 2

The Same Error occurred to me but in my case, I was using apache2 web server in Ubuntu VPS.

but doing

sudo chown www-data:www-data mysite/

and

sudo chmod 755 mysite/media

fixes the problem.