You can certainly have multiple images printed as a collage! You will need to create the collage image file on your end first, but there are some great, free websites that make it easy to do so. We would recommend checking out Fotor. Their collage makers are very straight forward, and easy to use. For something with a bit more advanced functionality, you can use a program like Photoshop, or the free web-based Pixlr.
Once you have the collage file put together, you can simply upload that to your chosen size on our website and place an order for the print.