Board Thread:Questions & Answers/@comment-27536054-20170505143151/@comment-7154338-20170505150342

You can find an already posted chapter/special operations picture and post your image directly in front of that so the size remains the same.

Example: http://maafanficuniverse.wikia.com/wiki/File:DC_C1_Cover.png

If you need a place to do that, I personally use the site ipiccy, but you can do it in pretty much any photo editing site. If you still need help, just ask.