RE: how do you reduce photos

If the picture is still too big here are somethings I do.

First look at the photo.
Cropping off unimportant features to make the image smaller saves memory.
Reducing the height and the width of the image reduces the file size by 4 times.
Reducing the colour depth of the image is also a good way to make the file smaller, though the quality issue is still there.
(If the image is black and white some memory can be saved by saving it as a greyscale image.)

The number of colours in an image is measured in bits or 2 to the power of a number.
An image with 16 bit colour doesn’t have twice as many colours as an 8 bit image. An 8 bit image has 2^8 colours or 256 colours. A 16 bit image has 65 thousand.
If you are processing an image to get information from it then the higher the bit setting the better, but for display or printing purposes the human eye can only differentiate about 16 million colours so 24 bit should be a limit.
In fact that is probably much more than you need and most people would be hard pressed to tell the difference between a 16 bit and a 24 bit image unless they were placed together.

The size saving is that a 24 bit image uses 24 1s and 0s per pixel to store the colour, whereas a 16 bit image would use 16 1s and 0s.
Of course Jpeg compression greatly reduces this but reducing the colour depth still reduces image size.