Reading through your KTB now, and wow I'm impressed
It looks just like a real thing, complete with notes on various events not recreated in game like preparations before patrol, and the style of writing is also like in real KTB's I've seen. If you've tossed it into uboatarchive.net you could probably fool most readers
So, I'll be rooting for Alexander Witt and hope to read more patrol reports from him.
On images: image size for your KTB entries is just fine, if you wanted to post something larger - I've been using Imgur to post images in my Subsim posts and so far never had problems with it.
And if you want to take the roleplaying one step further for your next patrols, you might consider having some fellow Subsimmers act as Doenitz as far as patrol review page is considered