How can I get a high-res image into LC?

[Tiemo Hollmann TB]

Hello,

when importing images into LC as an icon resource for buttons, does the dpi
of the image makes any difference?

I think the dpi is only relevant for printing. If I have a button of 100px
and assign to it an image of 100px it should be irrelevant if the image has
72 dpi or 300 dpi, it only has 100px in both versions. Am I right?

If I create an icon image with text in photoshop, I never get the text as
crispy, as real text because the image is a bitmap and the text is vector
based. And I don't even have a retina display for testing, so actually I
don't know how blurred the button images look like on a retina display.

What can I do to get crispy images (on buttons) in LC? How do you handle
this issue? Any workaround? Probably "100px always keep 100px" on the
screen, right?

Thanks

Tiemo