Ai PDF file size and Indd eps layers

[Matt54321]

AI can open any PDF, so having "some Illustrator capabilities" is no surprise.
Sounds to me like it's probably leaving Indd with a lot of damage done. Colors converted to sRGB, images downsampled (THERE's your filesize reduction) and layers lost.

Again, I've reduced filesize markedly when saving EPSs out of Illustrator or Photoshop by doubling or tripling the bitmap resolution and correspondingly halving or thirding(?) the overall file dimensions, which would be a wash except that the EPS preview component of the file is much smaller. It might work with a PDF, I think you should try it.

I wish I can get into specifics but I can't.

Here is the situation

the AI file is a set size, there are 3 layers, a txt layer, a graphics layer with no transparency or gradients and an image layer with a linked jpg color rgb image at.

This isn't going to print it is being loaded into the companies proprietary software that runs a script on the pdf to load in another proprietary application.