What are we talking about for image size (mb) and number of images?
You may need to use a different format and / or mosaic the images.
Jamal,
I don't believe ArcPad has a function/tool to add a significant number of orthophotos at once, even if its just 19. With little success, I have been working on adding several hundred images along a very long rail corridor into an ArcPad project. In ArcMap, I would utilize a raster catalog. However, raster catalogs don't work in ArcPad (see Technical article http://support.esri.com/cn/knowledgebase/techarticles/detail/25934). Here is one process used in exporting orthophotos to ArcPad (http://www.donmeltz.com/tag/arcpad/).