The units are in pixels. All units and guides are in pixels and points for text.
The problem is that I want to manipulate the dpi and see what it does to the pixels. I don't think of my web images in inches. I just don't. It won't let me select pixels because someone decided that I as a user didn't need pixels. If want to change the width to a smaller size and allow it to increase the dpi, I don't know what I'm doing in inches.
Inches mean nothing in web design, everything is defined by the pixel. If I want to lock the dpi and change the pixels, that's fine, but on as many occasions if not more, I reduce the dpi to 72, which will scale the image. I need to understand what that means in terms of web design, not print. Once I do that, I can often crop as I please or get close to the size I need and use the canvas size for the rest.
If you tell me something is 10" I don't know what that means in pixels. Great. It's 10 inches printed. I don't print, I am working on UI's for web applications and everything is 72 dpi. I'll have to do some crazy calculation to figure out what I'm looking at or bring it in and see what it does. guessing means it will be wrong and I can't sit around trying to guess how many pixels = inches. I never had this problem until I went onto the "cloud" which is a crock to make people pay more money and nothing else.
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