I use Microsoft word (in landscape view). Take an image from google, size it down to be the appropriate size so you can fit 4 pictures side-by-side. I put about 4-5 spaces in between each picture. I then insert text boxes below each picture to label the photo. I then use the "snip" program to take a screengrab and save that as a JPG and upload here.
To do the spoiler thing you need to type {SPOILER} MORE AND MORE LIKELY TO LOSE FOOTBALL GAMES BECAUSE HE'S A PIRATE{/SPOILER} but instead of { and }, use [ and ]
Also, when you make the post, do "Go Advanced" and add a title to your post, otherwise your spoiler will show up in the title bar and run the guessing game.
I haven’t did one in several weeks but I use MS Paint. I formatted it to the correct dimensions to look right and saved it. Then when I got ready to do another I’d copy the last one and swap out the pics and labels.