POST a file to https://up.anon.cat/upload, by default you will get a json response.
If you want a response in something else than json you add a flag to specify what format you want, for example https://up.anon.cat/upload?output=csv.
Valid response types are: json, csv, text, html and gyazo.
One file per request, up to 1 GB.
curl -i -F files[]=@yourfile.jpeg https://up.anon.cat/upload
You can also send the file as the request body instead of a multipart form, passing the name in the query string. This is the better option for large files: the length is known up front, there is no multipart envelope, and it is what the website itself uses.
curl -i -T yourfile.iso "https://up.anon.cat/upload?filename=yourfile.iso"
Both forms stream straight through to the CDN, so neither one is limited by the amount of disk space on the server.