If you’re looking to change the size of pixels in a photo or image in Photoshop, there are a few different ways to do it. One way is to use the Image Size command, which lets you specify the size of your image in inches or pixels. To change the size of pixels in an image using the Image Size command, open the image in Photoshop and select Image Size from the Tools menu. (You can also press Ctrl+I.) In the resulting dialog box, enter a new width or height value in inches or pixels, and click OK. If you want to change the size of pixels without changing the width or height of your image, you can use one of Photoshop’s pixel-editing tools. For example, you can use the Pixel Eraser tool to remove unwanted pixels from an image, or use the Gradient Tool to create a gradual transition between different pixel sizes. ..
How to change units (inches to pixels)in photoshop CS6
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