This never happened before and I do not understand it or know what it is. What is desktop.ini? I opened some of my folders with site pictures I saved them in and I saw it. It shows up in all my folders and has never done that before. Is it safe, or is it a virus? I noticed that if I delete it from the desktop folder, it changes the icon. I tried deleting it but then restarted my computer and it was back.
The desktop.ini files are typically hidden system files. They do, in fact, control the appearance of your folders, including any customized folder icons. When you delete the file, all the changes you made to that folder icon will be reset back to defaults. It is not a virus nor is it unsafe.
I can’t say for certain, but I imagine the reason you are suddenly noticing them is that you or someone who uses your computer recently set your hidden folders to be viewed. This is easily done in Windows 8. In the ribbon at the top of any folder, click on the View tab. Then, make sure to uncheck Hidden Folders. (To see the process for Windows Vista or Windows 7, see this article. )
Hiding hidden folders is largely recommended because most of these are required system files that you could do damage to your computer if they were changed or deleted. You will know if they are hidden because they are greyed out. Unless you know what you are doing, I would advise against changing hidden files.
Bonus tip – Want to know how to change the folder icons? It’s pretty easy! Right click on the folder you want to change the icon for, and click Properties. On the screen that pops up, click on Customize.
Notice I have the default folder picture displayed. At the bottom, click on change icon, and a list of icons will show up that you can choose from.
There is a browse option to choose a different location, but you cannot just use any picture as your icon. Generally, they need to have the .ico extension, or you can use a file with .bmp extension, or a .dll that have icons. In this case, I saved a picture of my daughter’s face as a .bmp and made it my icon. Or, rather than making your own, check out this archived Worldstart article about where to find and install additional icons.