Photo size terminology

[peggymarlatt]

Is 4M image size the same as 4MB?

Thanks so much for the answer to what is probably a very basic question! I am working on resizing photos of my artwork for show entry. I am not a photographer!

Peggy

[Just Shoot Me]

There is Mega Pixels (MP) and Mega Bytes (MB). Two totally different things.

MP (Mega Pixels) is the number of individual photocells, Light capturing devices, on a sensor.

MB (Mega Bytes) is the amount of space taken up for that file to store it on a hard drive/SSD/USB stick/whatever.

[Bani Verma]

Moving to Photoshop​

[Per Berntsen · Accepted solution]

If you are referring to the Image size dialog in Photoshop, M means megabytes (MB)

So in the screenshot below, the image size is 137.3 MB.

And the image is 24 megapixels (MP) - 6000 x 4000 = 24 million