Hardware: I use a good fast UMAX color flat bed scanner with a TWAIN SCSI interface.

Software: I mostly use PaintShop Pro for scanning images.

End: A beautiful image that loads fast. Or a thumbnail (little image) that allows the user the option to see a big image after a wait.

Means:

Let the scanner do the work. Adjust all settings to the intended size, resolution, color BEFORE you scan.

Explanation: Adjustments of size, resolution, color should be left as much as possible to the scanning software. Later editing of these properties may make the image blurry, grainy, whatever.

Size: The bigger the image, the slower it will load. Try 50% on your first scan of a normal size photo.

Cameras take pictures in pixels = dots.
The key measure is resolution, expressed in dots per inch, or dpi.
The higher the dpi, the greater the quality, the larger the computer file size.

Resolution: The maximum you can get on a VGA monitor is 72 dpi (dots per inch). So do not scan at 600 dpi.

Color: Choose Black and White for a line drawing, Gray scale for a black and white photograph, Color for a colored photograph.

Do a preview if your software permits it, then mark the area to be scanned, then do the scan.

Edit the image:
If your software did not let you pre-scan, crop the image. Rotate it if needed. Compare it with the original. Adjust the scan settings and rescan it if it differs too much in size or color or .....

SAVE AS:

myimage1.jpg if your original has many colors

myimage1.gif if your original has black and white or grayscale only, or fewer colors, or you need transparency.

Or use both formats, and then compare quality and file size.

Check on the size of your image:
Minimize your application. Open File Manager or Explorer. Look at the file size. If the image is under 20 K, fine. If it is bigger, it will load slowly -- start from scratch, maybe.

Examples, using a 6.5 x 4.5 inch color postcard from Aegina:

1) A little image:
scanned at True Color RGB, reflective, 100 dpi, 10% -- file size 2 K

2) A slightly bigger image:
scanned at True Color RGB, reflective, 100 dpi, 20% -- file size 6 K
 

3) A medium image, a little less than one fourth of the screen:
scanned at True Color RGB, reflective, 100 dpi, 50% -- file size 26 K

4) A big image, filling most of the screen:
scanned at True Color RGB, reflective, 100 dpi, 100% -- file size 87 K

Sample page with a clickable thumbnail linked to a larger image.