If i do anything with more than a couple images stacked on top of each other, i download them and knit them together using an image editor on my pc...much easier, then you just upload the finished image as a single file to imgflip...then you only have the text boxes to worry about!
I love Spuds' stuff, it's by far the most original use of memes/images i've seen here...good that he's sharing his techniques with you, the bastid tells me nothing!!! :p