I don't think so. You can always get a rough idea by just multiplying the left-most digit in the width and height. If your image is a wonky size, that will only get you close, but if it's 6,000 x 4,000, you'll know it's 24 megapixels.

Presumably you're talking about uncompressed size?
Jpeg size depends as much on the file itself as the dimensions, even if saved at '12' quality.

Presumably you're talking about uncompressed size?
Jpeg size depends as much on the file itself as the dimensions, even if saved at '12' quality.

That's the amount of memory the saved file uses, Sue, not the MP size.

Quote from: ShadySue on November 16, 2016, 17:10

Presumably you're talking about uncompressed size?
Jpeg size depends as much on the file itself as the dimensions, even if saved at '12' quality.

That's the amount of memory the saved file uses, Sue, not the MP size.

Yeah, I know about the pixel size, but that's not really precise. Also, if I use pixel size as a reference, I still have to divide it in my head or on the calculator by 3 to get only the rough number of megapixels. Funny that there is no number in the image resize box that would show the exact number in megapixels whenever you change the dimensions.

You have tweaked my curiosity here, so I tried modifying a couple of scripts (originally from istock contributor theasis and Sean Locke) in an attempt to do it...  you can get it from here:

MP Resize

Either right click and "Save link as..." or left click and copy and paste to a text file, then save as a ".jsx".

Put it in the Photoshop program directory under "Presets\Scripts" and it should become visible on the File/Scripts menu.

When run, it will display the size of the active image width and height in pixels, along with an approximate megapixel size (width x height).  You can enter a new megapixel size and it will display the approximate dimensions that would result, then when you're happy you can tell it to go ahead and resize the image if you want.  The result may not be exactly the size predicted (rounding errors I presume) but it should be close.

Caveat: I'm not a JavaScript programmer so I don't vouch for either the quality or the functionality.  It seems to work but use at your own risk!