Nice. The second one is especially compelling, with the rubble in the foreground.
As for image size, I usually just resize pictures
before uploading them to whatever photo-hosting site you are using (in your case, Imgur). I typically just resize mine in Microsoft Paint. There are many other apps that you can do it within (like Photoshop), but assuming you're on a PC, Paint is easy and free. I usually resize to 1024 pixels wide x whatever proportionate height. That seems to read well on a typical monitor display.
Resize Image In Paint