Can I increase images 300ppi that are embedded in illustrator?

[tarn_8092]

Hi there, I was wondering if someone could help me with this issue,

I have to prepare a file for print and some of the images are below 300ppi.

The images are embedded in illustrator and I dont have the packaged file.

When I click unembed and edit in photoshop and increase the ppi it doesn't increase the resolution in illustrator when I click on links after saving. 

Any suggestions?

My first thought was to get request a packaged illustrator file /original file and then increase ppi from those links. I also read somewhere sometimes you can't fix low resolution photos, thanks !

[Ton Frederiks]

Did you update the link after changing the resolution in Photoshop?

[tarn_8092]

Yes, i've updated the links after changing the resolution in Photoshop
It says update links are being updated, but doesn't update the ppi. 

[tarn_8092]

Most of the images are sufficient, except there are a few below 300ppi. Is there a way of increasing the ppi before sending to print?