Replacing banners content in an EPS file

Use the direct select tool (the white arrow) to select the image you want to replace. Then, from the links panel, you will notice that the image you selected in the layout is also selected in the links panel. (This will allow you to identify which of the unnamed embedded links you are working with.) With the desired image selected, you can click the little chain link icon to relink to the image of your choice.

If your image and the original image are not the same size or dimensions, you may notice that the relinked image has been scaled disproportionately. This is because illustrator forces the new image into the same dimensions as the image it is replacing. You can restore the new image to its proper proportions by selecting it in the links panel, then clicking "Placement Options." This will present you with a list of options to change the proportions. I recommend starting with "File Dimensions" and then using the direct select tool to fine tune the size and placement.

1. Click and drag an image file onto the page.

2. Scale it to the correct size if necessary by clicking and dragging the corner handles. Holding down Shift as you click and drag maintains the aspect ratio, preventing distortion of the image.

3. With the Direct Selection tool A, select the grey rectangle, and take a note of where it appears in the layers panel.

4. Click and drag the image under the grey rectangle

5. Move the image into position

6. Hide the grey rectangle

Example showing steps 3 to 6:

Note: If the image doesn't quite fit the rectangle, for example if it's not the same aspect ratio, you could also use the grey rectangle as a clipping mask to crop the image.

To do so, when the image is in the proper place, select both the grey rectangle and image. Holding down Shift as you target each object allows you to select both objects. Then click Object > Clipping Mask > Make or Ctrl+7 (Windows) or Cmd+7 (Mac)

Example: