I often receive content to be loaded on a website in the form of a Word document, and these often contain images that are unsuitable for website use. The picture at the right is 200 x 200 pixels with a file size of just 12Kb. It is displayed here at its 'natural' size. If it was displayed in this document at a different size (say) 100 x 100 pixels it would still have the same file size of 12Kb.
Many digital cameras take images of typically 4000 x 3000 pixels with a file size of 2,500Kb
In some of the documents that I receive the pictures are obviously straight from a digital camera. They are displayed in the document at a smaller size, but they are still very large files, maybe 200 times bigger than they need to be with obvious implications for storage space and download times.
The best approach is to determine the size required for desirable composition and scale the image to this size to the image file is only as big as it needs to be. You can use Windows Paint image editor to re-size a digital image.
If you need to re-size a large number of images you can use this free image re-sizer from Mihov Software. which allows you to resize a collection of images as a batch.