This post will explain why Illustrator and InDesign sometimes loses images and will show you how to avoid this in future. Let's go!
When you place images into a project, the default setting is that the images are linked. This means that the image is not actually stored in the Illustrator or InDesign file, but the information is fed into your project from an external location.
If you move the linked picture from one folder to another, Illustrator and InDesign cannot find the image any more. This is how you lose linked images. The Illustrator and InDesign files aren't smart enough to find your moved files - although they do recognise that they are missing,
When you open a file with missing images, the program will warn you that some are missing and you can either "replace" or "ignore". If you want to replace the images click "replace" and browse to where the images are or select with new images.
Why do these programs link images in the first place?
The reason why linking images exists is to cut down file sizes. Files with linked images are much smaller compared to when images are embedded. Imagine trying to work with a large InDesign or Illustrator file on a slow computer. A nightmare! Linking files can save time if this is the case.
I have a fast computer. I don't need my images to be linked.
If file size is not a concern for you and you like to clean up your drives regularly, embedding images is a save option. To do this go to the Windows tab (in Illustrator or InDesign) and click Links. This will bring up your Links palette. Highlight the images you want to embed and click the button in the top right. Then click Embed image. And voilà! Your image is now safely stored within the file.