Just use the GetThumbnail() function to get a smaller version of the photo to use on your reports. Do a replace before you generate your PDF.
I did once create a ScriptMaster function to step through all images in a PDF and down-sample them. Pretty sure its still somewhere on FM Forums
Advantage is that you can do other clever things at the same time.
FMP isn't massively smart about PDF creation from layouts and might bloat up you r file even with Mikes technique. I have a client with a 20k tiny, tiny, tiny image in the corner which is still producing 4MB PDF files.
I would 2nd Mike's comment about the GetThumbnail function. I've often created a container field for the report (or even for a layout) with an auto-enter calc using GetThumbnail with the size appropriate for the report or layout. That way, you retain the original, full resolution image.
Thanks for everyone's suggestions. I was hoping the GetThumbnail function would reduce the size of the PDF's but that hasn't turned out to be the case - it has only reduced them by a few hundred kb.
I've done a lot of testing and have even removed the Photos from the report and the PDF is over 7mb. Looking at the photos in the database and they are all under 100kb in size. When I add the photos back in the PDF is around 8mb.
So it looks like the base PDF without the photos is still very large - I can optimise this down to 1-2mb using third party PDF tools but that breaks the workflow and introduces a very manual step to the workflow which slows the staff down considerably.
The client is using FileMaker Pro v13 on Windows 7 - if anyone knows of a way to automate the optimising of the FileMaker generated PDF files I'd love to hear about it.
I guess it can really depend on what is on the layout for the report. However I have found Save as PDF generates larger files than printing to a PDF. Generally Save as PDF is 50% larger than printing. I am not sure if this can be scripted without using the print dialog box. In your case this might shave 2.5 MB off of the file. So there is still somehting else going on with a over large file.
You may want to look at things like background colors and other elements on the layout that may be adding data to the file. If the issue is that big it is not the images.