You can change the size of an image in Photoshop by using the Image Size dialog box. Here's how:
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Go to Image > Image Size: In the Photoshop menu bar, click on "Image" and then select "Image Size" from the dropdown menu. This opens the Image Size dialog box.
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Adjust Width and Height Dimensions: In the Image Size dialog box, you can modify the "Width" and "Height" fields to your desired dimensions. You can specify these dimensions in various units such as pixels, inches, centimeters, etc., by selecting the desired unit from the dropdown menus next to the Width and Height fields.
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Understand Resampling: The "Resample" option controls how Photoshop handles the pixels when you change the image dimensions.
- Resample checked (recommended for resizing): When "Resample" is checked, Photoshop adds or removes pixels to change the image size. Choose a resampling method from the dropdown menu (e.g., Bicubic Automatic, Bicubic Smoother (best for enlargement), Bicubic Sharper (best for reduction)). "Bicubic Automatic" is generally a good starting point. This option is generally what you want if you're physically making the image larger or smaller.
- Resample unchecked (changing resolution): When "Resample" is unchecked, Photoshop changes the resolution (pixels per inch/cm) without changing the total number of pixels in the image. This is useful for preparing an image for print at a specific size, where resolution is important, or for adjusting the resolution of an existing image without altering its appearance on screen. The "Width" and "Height" dimensions will adjust according to changes in the resolution field.
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Click OK: Once you've entered your desired dimensions and selected the appropriate resampling option, click "OK" to apply the changes.
Additional Considerations:
- Constrain Proportions: Make sure the "Constrain Proportions" icon (a chain link) is enabled if you want to maintain the aspect ratio of your image while resizing. If it's enabled, changing the width will automatically adjust the height, and vice versa. If it is disabled, you can adjust width and height independently, potentially distorting the image.
- Resampling Methods: Different resampling methods work best for different situations. Experiment to see which method gives you the best results for your image. If enlarging, "Bicubic Smoother" can help reduce artifacts. If reducing, "Bicubic Sharper" can help maintain detail.
- Image Quality: Enlarging an image too much can result in a loss of quality (pixelation or blurriness). It is generally better to avoid enlarging images significantly.
