To respond to this, perhaps I shouldn't overrely on Tumblr or Twitter as the source when uploading my own works, because they'll compress it to a smaller resolution, and I will get annoyed late when someone uploads the raw version and deletes my own upload, which would diminish my upload limit.

I think uploading my own artworks straight from the computer is the best bet even if the internet is really slow and the filesize is really big.

Also, on Derpibooru, when there's a duplicate or a better version, they kinda merge it instead of deleting it.