[skeb] Ignore thumbnail

[108EAA0A]

Currently, thumbnails are always downloaded.
Thumbnails are often low-res or blurred, and are not needed in many cases.
There needs to be a way to ignore thumbnails using options or other methods.

gallery-dl/gallery_dl/extractor/skeb.py

Lines 97 to 101 in c67756e

	if "og_image_url" in resp:
	post["content_category"] = "thumb"
	post["file_id"] = "thumb"
	post["file_url"] = resp["og_image_url"]
	yield post

[108EAA0A]

This is not directly related to this issue, but is og_image_url a thumbnail in the first place?
I think the actual thumbnail displayed on the user page is thumbnail_image_urls["src"] from the user works API(https://skeb.jp/api/users/{}/works).

[alice945]

I added a 'thumbnails' option in my pull request, disabled by default (#2051)
I choose to use the og_image_url thumbnail rather than the one on the main page because it is the highest quality, sometimes having a greater width than the preview.

[mikf]

As a more general solution, --filter "content_category != 'thumb'" would have also been possible.