What you need is photo-editing software. Even though you're not really doing advanced photo editing, you need that type of software to change your graphics file, just as you would need a word docor text editor to change a document.The solution is to use the Paint program, which comes with Windows.
This program is helpful if you don’t have the more expensive Photoshop.Open the image in Paint, and use File>Open to hunt that file down. Be sure to choose "All Picture Files" from the Files of type drop-down list. Otherwise, Paint will open only BMP files. (You should e-mail only JPG images.)Choose Image>Stretch/Skew from the menu. In the Stretch and Skew dialog box, locate the Stretch area. Type 50 into the Horizontal and Vertical boxes to reduce the image by half, or 50 percent. Click OK.
If that isn't small enough, repeat those steps. Don't forget that you can use Ctrl+Z (Undo) if you change your mind.Note: Some photo-editing programs let you resize by entering an amount in pixels. In that case, try setting the longest edge of the image to about 300 to 400 pixels, which is a good size for an e-mail attachment.After getting the size you want, resave the image.
Also, be sure to check JPEG from the Save as type drop-down list. That's the best file format for e-mail attachments.