A picture placeholder lets you graphically designate the location for an image and has the added benefit of letting you pre-determine the size of the image (height and width).
To use a picture placeholder:
On the desired slide, chooseInsert→Picture.
Select an image from your computer to stand-in for the merged image. (Any image will do.)
Placeholder Image:
We suggest creating or downloading a “placeholder” image to use as the stand-in for the merged image.
Using your mouse, size the image to the desired dimensions to determine which field will contain the image’s URL, add the merge field to the AltText property (located on Size & Position).
Right-click the image and choose Size & Position. Alternate method: Click Format (ribbon) → Size (group) → Size & Position (lower right corner)
Enter the merge field on the Alt Text tab (Description field).
Since the picture placeholder determines the dimensions of the final output, the merged image may be distorted if it isn’t designed for the dimensions of the placeholder.
Picture placeholders won’t work in Table cells. The output from this picture placeholder looks like this: