Thread image display issue

Here's an example of what I've been doing to make a thread title image at the top of my thread pages. There are definitely some various image display issues happening both in mobile & desktop. The display also gets messed up if there are multiple pinned posts. When I pin my post that has the image, the post shows with 2 images on desktop. I That fixes if I make another post. If I were to pin a 2nd post though, that puts the posts side-by-side, which breaks it looking like a banner. The images are also looking croppped on mobile instead of resizing down, so much of the image is cut off (which is why I resorted to doing these with just a small area of text in the middle.

Another bug: No matter where my cursor is in the thread, when I add an image, it always goes to the bottom of the thread & not where my cursor was. I'm able to cut & paste it where I want.