Start by opening the image you want to resize in Photoshop. Now you understand the importance of pixels and resolution, let’s look at where we use this when resizing an image in Photoshop. If the image is too big or too small, it’s going to cause problems. What’s important are the pixel dimensions (height and width) of the image. When that happens, the resolution is ignores in most cases.

That’s because most images now only appear on computer screens and the internet. Whilst this is useful information if you are going to print an image, most of the time you don’t need it. If an image is 5,616 pixels wide with a resolution of 300ppi, it would produce a print 18.72 inches wide that’s 5,616 pixels divided by 300. You just need to divide the dimensions of the image by the resolution: When you know the number of pixels and the resolution, you can calculate the size of the image in inches. This is the number of pixels in an inch if we were to print the image. The “ppi” after the number stands for Pixels Per Inch.

Usually this is written as a figure like 96ppi or 300ppi. The resolution of the image tells us how many pixels there are to each inch or centimetre. The aspect ratio is the proportional relationship between the two sides of the image (width and height).But if we wanted to state it’s size in centimetres or inches, we need another piece of information first. Next, decide whether you want to keep the aspect ratio of the original image. Many people use “Percent” for eyeballing relative size changes, but if you’re resizing images for the web, you’ll probably want to choose “Pixels” from the list.

Columns: This lets you resize by the number of columns, an arbitrary unit defined in Preferences > Units & Rulers.

Picas: One pica is equal to 1/6th of an inch or 12 points, and it’s used most frequently in design for print.

In a 72-DPI resolution image, one point is equal to one pixel.

Points: A point is a unit of measurement common in typography that is equivalent to 1/72nd of an inch.Inches, Centimeters, Millimeters: These are standard measurement sizes that only apply when an image is printed, and they are related to the image’s DPI.Pixels: This lets you specify exact pixel dimensions for the resulting image size.For example, using 50% as the target image size makes the image half of its current size. Percent: This lets you resize by a percent of the current image size.If you click the drop-down menu beside the “Width” or “Height” fields, you can choose the unit type. In the “Image Size” window, first, you’ll want to decide what measurement unit you’ll use to resize the image.

How to scale images in photoshop