Thanks for the question - firstly I have a lot of time on my hands
I do all my postings using Photoshop - I found the cat by the window image and the duck on a plane wing - put them side by side on one page. I took out the background of the duck - put a marque thingy around it and moved it over the cat by window image then reduced the scale 'till it looked right then saved it. Using the same program I also put the black borders top and bottom on all the images I post - I worked most of this out by trail and error and as a last resort, the online manual. Once you've sussed this program out, It's really not that hard - good luck
