I remember having a conversation with the client over the phone, about the correct size for inserting images into her website, using some content manager software. It went something like this:
Client: So whats a good size for images in the body copy?
Me: Around 150 to 200 pixels wide and high is usually enough
Client: How do I know how many pixels it is?
Me: It should tell you in the editing software you are using
Client: It only tells me in centimeters, I tried to measure it on the screen with a ruler, but I cant get the sizes to match..