You've embedded all referenced image files

If you’re using Illustrator to set up your file, you’ll need to ensure all images are embedded. An embedded image is fully contained within the document or a part of the document, and is not solely a reference to another location.

InDesign

Your linked images or files will automatically be embedded when you create your PDF document if you choose the [Press Quality] Adobe PDF Preset.

Illustrator

There are two ways to embed links in illustrator

1. From the Links panel, highlight the item(s) and choose Embed Image(s) from the dropdown menu.

2. Or, save the file as an Adobe Illustrator (.ai) format,

and then choose the option to Include Linked Files from the save dialog window.

Photoshop

Your linked images or files will automatically be embedded when you create your PDF document if you choose the [Press Quality] Adobe PDF Preset.