How can I make AI file be smaller size?

I had a similar issue on a an architectural rendering that I had inherited where images of a tree were scattered throughout the drawing for landscaping effect. I created one tree as a symbol then used a script to replace the other placed jpegs of the tree with the new symbol. Here is a link to a script that should work: http://www.jon.hk/2017/07/adobe-illustrator-batch-replacing-objects/

I sense the JPG has been scaled down to fit your pattern and it is embedded.  Not sure what size you are working in, but try resizing the JPG in Photoshop and "Place" the file in Illustrator at 100% ( when you Place the image, make sure the "Link" is selected in the dialogs ).

It might be a weird answer. But I make symbols in largw files from certain elements and this will make the file smaller.

Try it and see if it is working.

Chana

Sounds like you used an option other than grid, when making the pattern. Unfortunately in my testing the brick and hex options make an additional linked copies of each placed .jpg, and that makes your files large and  slow.

There is no solution for this exact issue, but would suggest posting a bug request

Feature Request/Bug Report Form

Logically would appear that the Adobe development team, should be bale to reprogram this to only use one link for hex and brick options, but not sure how difficult that would be of them.

Can we see a screenshot of your art, you may be able to use live trace to make this vector, our suggest something else that could help your large file size.

Do you need to exchange the file inside the Creative Cloud? That is: place it in InDesign, open in Photoshop or the like?

If not, save it without "PDF compatibility"

If this does not help or does not apply to you, please give us more details about the file and your workflow.