Resizing images in photoshop is a subject that a lot of people ask questions about. Resizing is very easy with the newer versions of Photoshop.
The correct way to resize an image is through the Image Size window. Go to the main menu then [Image->Image Size] a window with various settings will appear:
When resizing an image you need to determine whether you are enlarging it or reducing it’s size. Using the wrong settings for either can result in non-optimum image resizing.
1. Ensure that the “Constrain Proportions” settings is checked “on”
This will ensure that when you resize your image, it won’t get stretched in any way while resizing the image. If you want to change the image proportions, you can do this later using the crop tool or the canvas size window which I will mention later in this tutorial.
2. Ensure the “Resample Image” setting is checked “on”
When Resample Image is set to on your image actually changes size when you change the image dimensions under “Width” and “Height”. If you try to resize the image with the Resample Image unchecked the only thing that will change is the resolution.
A note on resolution: The resolution of an image can be changed without resampling the image. If you change the resolution without “Resample Image” setting on, all this will do is change the width and height of the image in inches (or whatever measurment you set it to). The images pixel count will remain exactly the same. When the Resample Image setting is on the images pixel count will change. I will illustrate this below.
As you can see, the “Resample Image” setting is important when you want to resize an image.
3. Decide if you want to “Scale Styles”
If you have an image with 1 layer, you can ignore this setting. The “Scale Styles” setting tells Photoshop whether to scale styles on layers. For example, you can put styles on layers, Stroke, Bevel, Drop Shadow, Etc.
If Scale Styles is on, strokes and drop shadows settings will increase appropriately to the new size. If you have a small image with a 1 point stroke and you scale it up, the stroke will get thicker in the correct proportion. If you resize the image with “Scale Styles” off the stroke will remain at 1 point no matter how big or small you make the image.
The above image illustrates the use of the “Scale Styles” setting. As you can see, this setting is only important if your image has layer styles in it.
4. Set the correct scale setting
Choose from the dropdown a correct scale setting. I will list the settings and when they should be used:
Nearest Neigbor: Use this setting when sizing images with hard edges. Images with solid colors and sharp lines will best be resized with this setting. Do not use this setting for Photographs.
Bilinear: Some pictures can be upsampled pretty well with bilinear interpolation. But we usually use one of the bicubic options below instead.
Bicubic (Best for smooth gradients): Bicubic is the best for photographs and smooth colors. Photoshop gives you 3 different bicubic settings. I suggest using either of the 2 below for resizing your images unless you have a lot of smooth areas in your image with blurred adges.
Bicubic Smoother (best for enlargement): Use when enlargement of images, using this setting will produce the best for making images and photos larger because it smooths out the image a bit to produce better detail quality.
Bicubic Smoother (best for reduction): Use when reducing the size of images, using this setting will produce the best results for making images and photos smaller because it keeps the feeling of the original sharpness of the image.
5. Set the new size for your image and press OK
You can change the size of your image in numerous areas. You can change any of the numbers under “Pixel Dimensions” and any of the areas under “Document Size”. You can change any one of these settings to change the image dimensions. Now click OK and your image will be resized.
Image resizing Summary
- Ensure that the “Constrain Proportions” settings is checked “on”
- Ensure the “Resample Image” setting is checked “on”
- Decide if you want to “Scale Styles”
- Set the correct scale setting
- Set the new size for your image and press OK
An additional Note: You can resize images in your Photoshop file by using the Free Transform tool, be sure to set the correct Image Interpolation setting by going to “General” in the Preferences Window and choosing the right setting as gone over under step 4 above. When resizing with the Free Transform tool hold down “Shift” to keep the image proportions the same (Prevent stretching the image).
Now that I have shown you how to properly resize an image in Photoshop I will show you how the Canvas Size window works, so you know the difference.
Canvas Size Window
The Canvas Size Window allows you to crop an image using the width and height dimensions.
The canvas size window is much simpler than the Image Size window.
First change the width and height to be larger or smaller.
Next set the anchor where you want it. If the anchor is in the center, the width or height will be added or removed equally around the image. If the anchor is on the right in the middle, any changes to the width will happen to the left of the image. You have 9 different anchor positions depending on what you want to do with the image.
Finally, pick a color in the Canvas extension color area. This will set a color to any area you add to the image (See example below)
Below is an example of using the Canvas Size window to alter the left side of an image.
This image shows the original image on the left. The image in the center shows area added to the image with the Canvas Size (Red area added). The image on the right shows the left side of the image cropped with the Canvas Size Window.
Canvas Resizing Summary
- Change the width and/or height dimensions
- Set the anchor where you want it
- Pick a color in the Canvas extension color area
- Press OK