Upload & Sell: On
It's almost like cheating to use third party - the prices are ridiculously low. You cut these out yourself in Photoshop so you know what kind of time it takes. There are two choices I have tried, both were under $2.00 per image (yes, you read that right) and they do a great job.
Rebooku.com and Photoshopit.com are the two I used this year - both were equally excellent and similarly priced. I'm pretty sure Paul (P Alesse) is a Rebooku guy, but I'll let him check in with that info. I'm a ham-and-egger compared to him, so his recommendation should carry far more weight. In any case, it will make those posters MUCH more fun to create. My workflow for those would be to make rough cutouts (and I mean ROUGH - no more than a minute each) so you can put them on the template and size/arrange to taste, then send those images off to be extracted once you're satisfied with the look. When the images come back you simply plug them in and delete the rough ones as you go and you're done. That way you don't have to try to remember how you had them arranged on your draft copy.
I believe both sites I mentioned give you a few free images as a trial, so if $2.00 a throw is more than you want to spend to be convinced, you can be persuaded for free (and you WILL be persuaded). Run, don't walk, to either (or both) of those sites and give it a go.
FYI - if you should, for some reason down the road, decide you need to cut out those masks (or something similar), I have found the best method is to zoom in as tight as you can on the image, size your brush to match the width of the bars in the mask, click on one end of a bar then move the cursor to the other end and shift+click. It will mask a straight line from your first point to your second. Rinse and repeat for the rest of the face mask and voila!
All the best!