1. Adobe Photoshop
- Open your image in Photoshop.
- Go to Image > Image Size.
- In the Resolution field, enter your desired DPI (e.g., 300 DPI for print).
- Ensure Resample Image is unchecked if you want to maintain the current pixel dimensions (this only changes DPI metadata without altering actual pixel data).
- Click OK to save changes.
2. Adobe Illustrator
- DPI is controlled when exporting or saving files, as Illustrator primarily uses vector graphics.
- Go to File > Export > Export As (choose a raster format like PNG or JPG).
- In the export dialog, set the resolution (choose High (300 PPI) for 300 DPI).
- Export your file to apply the DPI setting.
3. GIMP (Free Software)
- Open your image in GIMP.
- Go to Image > Print Size.
- In the Resolution fields, enter the desired DPI for X and Y (typically, both should be the same).
- Click OK to apply.
4. Microsoft Paint
- Paint does not have a direct DPI setting. However, you can change the DPI by resizing the image to the desired pixel dimensions for printing at a specific size. To calculate pixels needed: multiply desired inches by DPI (e.g., for a 5×7 inch at 300 DPI, resize to 1500×2100 pixels).
5. Online Tools (e.g., Convert Town, DPI Converter)
- Upload your image to an online DPI converter (such as Convert Town’s DPI converter).
- Set the desired DPI, and download the updated image.
Tips:
- For web images, DPI generally doesn’t matter; screen resolution depends on pixel dimensions, not DPI.
- For print images, 300 DPI is standard, but you can go higher for extra detail, especially for large-format prints.
These methods ensure your image has the correct DPI setting for your intended use, particularly for print quality.