You can be sure anyone selling digital images of licensed products is doing so illegally. I can't believe that people selling copyrighted images don't know it is wrong. I see people writing disclaimers saying they don't own the image, and that it is for personal use only. It doesn't matter, distributing these pictures is wrong even if you don't charge a dime for it. Even if you are only "charging" for creating the sheet and not the graphics themselves. You are still DISTRIBUTING copyright protected images. Would you be ok with someone creating an image sheet with the cute graphic you use in your logo? It's ok if they offer it for free right? For a company (or a person) to sell an item (for example stickers you buy in a store of mickey mouse) you must buy (and have your product approved and in many times your business, your work conditions etc approved by the person holding the copyright to the images) The company that wants to print the sticker of Mickey Mouse not only has to purchase the license but they have to pay a percentage of each sale to Disney as well. You can be sure Disney, NFL, Ford, etc are not going to allow their logo's and images to be sold DIGITALLY to anyone. Even if they did, I highly doubt people selling image sheets on Etsy, their website or wherever are shelling out $100,000 for a license to sell Hello Kitty images.
Please note this rant was not aimed at the user who posted this question or anyone else curious as to the legality of selling licensed images. I'm glad you have the morals to ask! I just can't believe the big sellers on ETSY or wherever think they are entitled to freely use any image they can get their hands on.