Printing Services

[agarzaldynrd]

I want to print some of my lo but I have some questions. Hopefully someone can help.
First, and most important because I want the Feb. collab kit , does this purchase count towards getting that free?
2. I have saved all my files as JPEGs in addition to PSD and Web-ready. I think I print the JPEGS but how do I know if they are the right size and dpi? I don't even know what dpi means!!!
3. Some of my JPEGS aren't 3600 x 3600. Does that mean that I saved them wrong? How do I fix that??

OK, I'm sure I have more ???? but I'll wait for a response and see where I am after that.