You should be able to hide this one (or the other) by clicking on the three dots somewhere on your post. It'll give you the option to edit, report, hide, etc. Hiding is the same as deleting a post.
To post two images together in the Gallery, you can upload one image as the primary gallery image, and then upload the second image inside the text box that makes up the caption. (The "attach or choose files" option is at the bottom of every text box.) Otherwise, you could make an art thread if you'd like, in the Fanworks subforum, or the Creative subforum (either works). A thread is good if you want to post lots of images related to one thing.
Ais fanart #2
in General Art
3Posted
Thank you so much for the help! Found it ^^