Open your graphic design program and create a new document. Most programs will prompt you to input the specs of the project as you're creating the document. Input the width and height you want. Be sure that the settings are at a high quality to ensure that the design translates well in print or online.
Select "Open" and choose the background image you want to use. Copy and paste this image into the document you have created. You can also select a color or color gradient to use as the background.
Download, scan or save the images that you want to use in your collage. You can find images on the Internet, on free stock image or clip art websites, and in clip art books. You can also create images using the painting or drawing tools in a separate document of your graphic design program. Scan hard-copy images that you would like to use in your collage at a high resolution, then save them in an easily accessible folder.
Open the images that you want to include in your collage. Modify them in any way necessary to make them easier to place in your collage document. For instance, if you want to remove the background from an image, use the lasso tool to select the background, then remove it using the delete or modify tool, depending on the design program. Modify all images before importing them into your collage document.
Copy and paste the modified images into the collage document. You can paste them anywhere in the document, then select them with the hand tool to arrange them as you like. Arrange the images in a related and aesthetically pleasing manner.
Add special effects to the collage, including drop shadows, typed captions or warped corners. These effects can help the images stand out or blend with the background, depending on what effect you're trying to create.
Save the file in an accessible place on your computer. Back it up on external hard drive if necessary.