I'm in Adobe Illustrator 2022 26.064 and I'm placing an item. It is the thirdone I place in the same document.
var placedItem3 = doc.placedItems.add();
placedItem3.file = new File("/c/files/dotfiles-win/illustrator-scripts/lorem-picsum/3to2-1080x720.jpg");
placedItem3.name = "placedItem3";
For some reason it gets placedItem.width=3061,41 ,placedItem.height=2040,94
When the file is 1080x720
The previous items were placed keeping the same dimensions of the file.
You can find out ppi of a image with the formula:
72 / image.matrix.mValueA
For example here is the script that finds images with ppi less than 250 and selects them:
var min = 250; // target ppi
var rasters = app.activeDocument.rasterItems;
var i = rasters.length;
while (i--) if (72/rasters[i].matrix.mValueA < min) rasters[i].selected = true;
Illustrator does it in a rather uncommon way via the transformation matrix
I'm not sure if there are another ways as well. And probably it might require additional steps for rotated images.