Technical requirements for photos - image resolution

[Mickey98]

Under photo and illustration requirements, the user guide says the minimum image resolution must be 4 MP.

In my copy of Photoshop, the default resolution (under image size) is 300 ppi.  What does the 4 MP requirement mean?

[Nancy OShea]

Megapixels = your camera's specifications.

Modern iPhones and iPads are 8-12MP.

Most entry level DSLRs are 16-24MP.

[Mickey98]

Thank you for your reply.  It was very helpful.

Mickey98

[Test Screen Name]

To get the exact size in MP (megapixels):

width in pixels x height in pixels / 1024 / 1024

Ignore ppi, it has no relevance to stock graphics.

[Nancy OShea]

Multiply height in pixels times width in pixels and divide the product by 1 million.

Laptop screen is 1920 x 1080 px. 

Multiply 1920 by 1080 to get 2,073,600.

Then divide by 1,000,000 to get 2.07 MP.

PPI (pixels per inch) or DPI (dots per inch) are used for print purposes only.