You can't do it in Photoshop.
Photoshop uses bitmap images, meaning that the images you create are built from coloured pixels. If you have a small thumbnail size image that is 50 x 50, and you enlarge the image to a 200 x 200 pixel image, then you've basically increased the pixek count 16 times. Instead of the a blue being 1 pixel, it's now a large square that is 4 pixels wide and 4 pixels tall.
The image, regardless of how large you increase the size, will always retain the original 50x50 ratio. |
