Megapixels (MP) represent the pixel dimensions of a file, where 1 megapixel is equivalent to one million pixels. To go from resolution to megapixels, calculate (width x height)/1,000,000.
A photo that is 3000 pixels by 2000 pixels is 6,000,000 pixels or 6 megapixels (3000 * 2000)/1,000,000. The megapixel range varies from camera to camera.
Megabytes (MB) represent the file size of an image or how much space it takes up stored on your computer. The more you compress your image when exporting, the smaller the file size, but the quality of the image is also lowered. We recommend exporting images at maximum quality without any compression.
We recommend exporting images at the maximum resolution of your camera without any upscaling and with the highest possible quality.
To find the dimensions and size of your files:
Right-click on the file > Get info.
You can find the file size in MB under General > Size and pixel resolution under More Info - Dimensions.
Right-click on the file > Properties
You can find file size in MB under General > size and the pixel resolution on the Details tab under Image - Dimensions.
Image > Image size
Library > Metadata card