Hi, I have this issue.
I created a 2000x2500 px with 300ppi file in Photoshop.
When I import the PSD to Illustrator (Illustrator same size and ppi) the PSD is auto resized to 480x600 px with 300 ppi. If I resize it this PSD, on Illustrator, back to 2000x2500 it say 72 ppi.
The image still has the same amount of pixels (see the Links panel) there are just more of them in an inch.
What you are seeing is just a difference between how Photoshop and Illustrator count pixels. Nothing is wrong. The fact is THERE IS NO SUCH THING AS A SIZE IN PIXELS IN ILLUSTRATOR. Only a size in inches or mm. If you see "pixels" in Illustrator it means, exactly and always 1/72 inch, without taking resolution into account.
So, you make a 2000 x 2500 pixel file in Photoshop at 300 ppi. That is 2000/300 x 2500 / 300 inches, about 6.67 x 8.33 inches. You place it in Illustrator at its natural size, and it is still 6.67 x 8.33 inches. You ask for the size in pixels in Illustrator and it divides by 72, so it reports 6.67 * 72 by 8.33 * 72 "pixels"- 480 by 600 "pixels".
The bottom line, and it can be a painful lesson:
1. You can't work in pixels using Illustrator
2. So don't try
3. If you feel you still need to work in pixels in Illustrator go to step 1.
There is nothing wrong with working in pixels especially when you are preparing artwork for export as images.
Many times users have complained about additional semi transparent pixels when exporting as an image. Often caused by working in inches or metric units.
Your example of 6.67 x 8.33 inches shows that perfectly. Converting from inches to pixels does not give the round number you show: 480 by 600 "pixels”, but 480,24 px X 599,76 px
When exported you will get the dreaded additional pixel.
Working with pixels as a unit would have shown the fractional pixel value, which could have been corrected before export.
The bottom line, it can be a painful lesson to avoid pixels.
If you don't like pixels as a unit, you can also use points.
To work at the full (pt/px) size in AI, you can:
Either create/change (a version for use in AI of) the file with 72PPI and just use that in AI;
Scale the file up in AI; you can do that by dividing the W or H value by 0.24 and restrain proportions, or you can scale uniformly by 10000/24 %.
Use a physical measure in Illustrator not pixels. So 6.667" x 8.333".
Illustrator has Doucment Raster Effects, but that is not the same as resoltuon pixels per inch in Photoshop.
If you create a new 2000 x 2500 pixel doucment in Illustrator, then switch to inches, you get a much larger canvas.