MY CARTHow to Change Image Size in Photoshop:
This video lesson, titled “Learn How to Change the Image Size and Resolution in Adobe Photoshop: A Training Tutorial,” shows you how to change image size in Photoshop and also change image resolution in Photoshop. This video lesson is from our complete Photoshop tutorial, titled “Mastering Photoshop Made Easy.”
Overview:
All images must appear as pixels onscreen when using a computer display. So, before you can manipulate the images, you must learn how pixels are displayed and measured within computer displays. When an image appears on a monitor, it is rendered according to the pixel dimensions of the graphic and the display settings and size of the monitor.
The image’s pixel dimensions are the width and height of the image in pixels. The number of pixels displayed in an image is measured in pixels (dots) per inch or pixels (dots) per centimeter. This is also called the ppi or dpi. Generally, the higher the ppi or dpi, the higher the image quality.
The digital size of an image, usually measured in kilobytes, megabytes, or gigabytes, is proportional to the pixel dimensions of an image. Images with a higher ppi/dpi have a higher resolution and produce greater detail when printed, but they may also print more slowly and take more disk space for storage. Photoshop supports a maximum pixel dimension of 300,000 x 300,000 pixels per image.
How to Change the Size of an Image in Photoshop:
To change the size of an image in Photoshop, select “Image| Image Size…” from the Menu Bar to open the “Image Size” dialog box. The current digital size of the image appears next to the “Image Size” label. Its current pixel dimensions appear in the “Dimensions” section. To show the image’s dimensions using a different metric, click the drop-down arrow next to the “Dimensions” label and select the desired metric from the drop-down menu to see the measurements of the image for that metric appear, instead. To show pixel measurements, select the “Pixels” choice from this drop-down menu.
Size Options:
To resize the image to fit a selected preset, choose the desired image size preset from the “Fit To” drop-down. Alternatively, to manually specify dimensions and a resolution which you can save as a preset, if desired, enter number values for the width and height into the “Width” and “Height” fields and then use their adjacent drop-downs to select the units of measurement for those values. To disable proportionally scaling the width and height values together, if needed, click the chain-link icon to the left of the height and width dimensions to toggle it off.
Resolution Options:
To change the resolution of the image, or ppi/dpi, enter the desired resolution number value into the “Resolution” field and then select the unit of measurement for the resolution value from the adjacent drop-down. To resample the image when resizing it, check the “Resample” checkbox. Then use the adjacent drop-down to select the interpolation method of resampling to apply. If you do not resample an image when resizing it, you instead change its resolution.
To not change its resolution, you resample the image to add or remove pixels using a selected interpolation method. When resampling an image, if you increase the image size, you add new pixels to the image. Photoshop adds the new pixels based on the color values of existing pixels in the image. You can generally resample down and not lose image quality. However, resampling up, or adding pixels, often results in an image that is a bit blurry.
Interpolation Options:
For the methods of interpolation that you can select from the drop-down, selecting the “Automatic” choice lets Photoshop use the interpolation method it thinks is best based on the data in the image. The other interpolation methods listed in this drop-down show the situation in which you may want to try using them within parentheses at the ends of their names.
If one interpolation method doesn’t produce the desired effect, you can try using another, if needed. For example, if you find that enlarging an image using the “Preserve Details (enlargement)” interpolation method produces undesirable results, you can undo your changes and then try it again using the “Preserve Details 2.0” interpolation method. Also, note that the “Bilinear” interpolation method, which lacks a helpful description, adds pixels to an image by averaging the color values of surrounding pixels to produce medium-quality results.
How to Scale Styles and Finish Resizing the Image:
To scale any styles applied to the image when resizing, click the “Set additional Image Size options” button, which looks like a cog icon, in the upper-right corner of the “Image Size” dialog box. Ensure there is a checkmark in front of the “Scale Styles” command in the menu that appears. If not, click it to select it to enable that resizing option.
To finish and resize your image in Photoshop after setting the “Image Size” options, click the “OK” button in the “Image Size” dialog box. Alternatively, to cancel the resizing, click the “Cancel” button.
