It can be done in at least 2 ways, both require some programming experience.
1. Create for example. 50 unbound image controls on a form when the form is opened, the control source for each image control is set for the desired photos. Unused image controls are set to invisible.
2. Create a "master" form and using VBA code copy it and put the copy into design view (hidden), create the required number of image controls on the form and the required properties are set for each image control when all image controls are created, the form is saved and afterwards opened in Form view, everything is done using VBA code.
Controls are created in VBA using CreateControl.
As you mention Word as an alternative I'll mention the Report, I think you can do it in a report, by setting it to 4 columns and set the "Column Layout" to "Across, then down".