File size, which I've learned limits the sizes I can sell. I don't have any software that I pay for, I haven't found any that I can afford that seem worth it for me. I usually just post straight out of the camera. If I edit, I use the simple software that my computer came with. I've also tried free editing software sites, but they lower my file size a lot more than my computer. For instance, if I edit a photo through my computer it only falls from 5 or 6 MB, to about 2 or 3 MB; if I use free software from the internet, it goes all the way down to below 1 MB.