It seems like you can do this via the Default Value item in the field properties but when I add the path to the image I want, and then create an item with that template, it doesn't show that image. If I click Browse it puts me in the source folder I specify, which has that default, but is there a way to prepulate the image into the item without having to go in and select it manually?
This is what Standard Values are for. You can set the value of the field on the
__Standard Values item underneath the template of the item you're creating (or a base template, if you prefer):
__Standard Values item does not exist under your template, you can add it:
- Select on your template in the Content Editor
- Ensure the Builder content tab is selected
- In the Builder Options ribbon tab, click the Standard values button
There's also another question/answer with more information on the difference between Default Values and Standard Values.