if you have adobe photoshop then it will be better to change.
From there, right click and open with Paint
Click on Image > Stretch/Skew
For this example, we’ll make it 50% smaller by entering 50% in for the values by Horizontal and Vertical (keep the numbers the same to maintain the same ratios) and click OK. For an Avatar, you’ll probably want a higher number to make it smaller.(make ur own ratio)
Now do File > Save As and either keep the same name or rename it something like "Filename_small".
Check your image size...voila! This image went from 1024x768 to 512x384
or
open in photoshop
click on image and then change size and put ur required resolution size.
