There is a Property of the Bound Object Control specifying Thumbnail or
Icon -- be sure it is set to "Thumbnail".  But, even so, you are limited
because Access must work with whatever software is registered by the user to
handle the image file type. If the registered software doesn't provide
appropriate capability, Access can't do what you want.

The sample imaging databases at http://accdevel.tripod.com illustrate three
approaches to handling images in Access, and the download includes an
article discussing considerations in choosing an approach. Two of the
approaches do not use OLE Objects and, thus, avoid the database bloat, and
some other problems, associated with images in OLE Objects. Access 2007 has,
I am told, eliminated the bloat problem, but you are still "held hostage" to
whatever software the user has registered for handling the image file type.

If you are printing the images in reports, to avoid memory leakage, you
should also see MVP Stephen Lebans' http://www.lebans.com/printfailures.htm.
PrintFailure.zip is an Access97 MDB containing a report that fails during
the Access formatting process prior to being spooled to the Printer Driver.
This MDB also contains code showing how to convert the contents of the Image
control to a Bitmap file prior to printing. This helps alleviate the "Out of
Memory" error that can popup when printing image intensive reports.

Larry Linson
Microsoft Access MVP