create a new calculated field in the same table of your container ( I assume for this example that the name of your container field is "container" ) with this calc:
ValueCount ( container )
Now, while in Browse Mode, do a find on that new field inserting 3
How many records do you find ?
we went with filemaker specifically because it saves the photos as part of the database - correct?
It depends: if during inserting the image you check the option "Store only a reference to the file", then no. In such case, the container stores only the path to the image file - and when the path changes, the images won't be found.
This MIGHT be what you describe - it's hard to tell without a better description of what the field actually shows (a message, an icon ... ) and especially what a calculation = GetAsText ( YourContainerField ) would show.
To further clarify....
Raybaudi's suggestion is a test to see which container fields, if any, might be store by reference and thus not storing the actual image.
Comment is explaining the how and why of the same issue.