I always thought that Pixiv sources were to be favored over such sources as Twitter, hence they would be set as 'parent' if multiple sources for a post existed no matter when the post was uploaded. Has this been changed? What is the stance now?
Posted under General
I believe the guidelines in help:post_relationships are still valid.
The Pixiv version doesn’t always get to be the parent, but it often does because Twitter mangles images with stronger compression. Sometimes artists upload high-res images to Twitter and downscaled versions to Pixiv. In that case it’s up to you to decide which version is “better” if none of the aforementioned guidelines help you decide.
One case where Twitter wins over Pixiv in parenting is artist #41000, as the artist uploads pngs to Twitter and jpgs to Pixiv.
And then we are left with cases such as artist #133085, which posts Pixiv images that are almost identical in all aspects to the Twitter image except file size, and even that is very close to similarity. This has been recently brought up in topic #16429.