You do realize 100% on a retina display is not the same as 100% on a monitor set to 1024x768 right?
It is the screen resolution that determines what 100% is.
The higher the resolution, the smaller image will be as is true for the image resolution, the smaller the image resolution is the smaller the file.
You are comparing the image resolution to the image resolution. (When specifying a percentage)
Ah, no, I don't guess I did realize that.
What would be the best way to go about working on things, then? Will I just have to settle with working on things at 200% in order to make sure I know what the size is going to look like on the web?
As for comparing how it looks using fit screen or fill screen can be of help. But frankly photoshop doesn't really have a pixel setting for the zoom level to verify it is the same size on a different monitor. You could temporarily set the screen resolution to a smaller setting. But for the web, that is kind of defeating the purpose of the web. Images are suppose to be fluid (percentages) rather than fixed (pixels) so that it looks good on all monitors.
Knowing that would mean it would be scaled different depending on the monitor with no real way to verify its look.
As a work around, most browsers can now change the layout of the web page to a fixed monitor size. Same for web design programs like Dreamweaver. So all is not lost.
It maybe worth your while to do a feature request. Ask if they could add monitor simulation modes or adjustable zoom by pixels.
Alright, thank you for all the help! A lot of that stuff I didn't know, so it's good to learn. I'll do what I can for now, and take your suggestion for a feature request. Thanks again!