A collage can be created using the Collage Editor dialog. Once the collage is completed, a new project with the selected images is created. The result can be further modified like any other photopad project.
Opening the Collage Editor dialog
To open the Collage Editor dialog, click the Collage button on the Creative tab of the toolbar, or select Create Collage from the Tools menu.

Collage Editor dialog reference
Canvas Options
Click on Canvas Options to expand the canvas controls. Use these controls to adjust the overall size of the collage.
Select the size of your collage with the Collage Size pulldown list. The options listed are in inches by default. Use the Units pulldown list to change the collage size measurements to Centimeters or Pixels.
Click the Landscape button for a horizontally oriented collage, or click the Portrait button for a vertically oriented collage.

Background Options
Click on Background Options to expand the background controls. Use these controls to change the background of the collage.
Select the Solid Color option for a single colored background. Change the color with the Background Color color button.
Select the Custom Image option to use an image file for a background. Select the image file with the Open Image button.
Layout Options
Use the Layout Options controls to change how images are arranged.
Use the Auto Grid layout style to pack an arbitrary number of images into a grid layout.
Use the Free-form layout style to arrange an arbitrary number of images randomly.
The remaining layout options are premade templates that only support a limited number of images.
Use the Spacing slider to increase or decrease the spacing between images.
Use the Rounded Corners slider round out the edges of images.
Use the Random Tilt slider to randomly tilt all images in the collage.
Use the Randomize Layout button to scramble the images.

Image Options
Click on Image Options to expand the image controls. These controls can only be used when you have an image selected.
Use the Assign Image button to replace the currently selected image with a different image.
Use the Remove Image or the delete key to delete the selected image.
When using the Free-form layout and the selected image is under another image, use the Move Forward button to change the overlap.
When using the Free-form layout and the selected image is on top of another image, use the Move Back button to change the overlap.
Adding Images
Use the Add Images... button to add more images to the collage. If you already have more images than the layout template allows, the additional images won't be added.

Finishing the Collage Creator dialog
When satisfied with the results, click the Create button. A new PhotoPad project will be created, with a collage layer that contains all images from the Collage Editor. Click the Edit Collage button to reopen the Collage Editor for further editing.