Summer means holidays. Holidays mean photographs. Lots and lots of photographs.
If you're like me, when you get home and go through them, you'll find a few that you want to do more with. Or one special one that would make a perfect painting, but you just don't have the artistic skills. And if you're really like me, you'll wonder if there's some technology to help you make the most of them.
The free versions of both apps have their limitations. With Prisma you need to pay to unlock HD quality and many of the styles while Deep Art shows ads while it is processing the image and places a small watermark in the bottom corner of the final picture. But I think the end results are worth it.