Despite the quite unambiguous definition, the concept of digital image resolution today has a dual meaning. This term is called both the logical resolution (a characteristic that determines the relationship between the number of image pixels and the actual dimensions when outputting to various devices), and the dimension of the raster itself. You can make the image resolution suitable for its use for certain purposes in the editor Adobe Photoshop.
Necessary
installed Adobe Photoshop
Instructions
Step 1
Load the image you want to resize into Adobe Photoshop. Expand the File section of the main application menu, and then select the "Open …" item. Alternatively, you can press the keyboard shortcut Ctrl + O. A file open dialog will be displayed. Go to the necessary directory in it, select the file with the picture and click "Open".
Step 2
Open the dialog for managing the geometric parameters of the image. Use the keyboard shortcut Ctrl + Alt + I. You can also sequentially select the items Image and "Image Size …" in the main menu.
Step 3
To change the physical resolution of the image, activate the Resample Image option. In the group of Pixel Dimensions controls, the Width and Height values become editable. If you need to change them proportionally, activate the Constrain Proportions option. In the drop-down lists of the Pixel Dimensions group, select the units of measurement (pixels or percent), and in the lower list of the dialog, select the image interpolation method. Enter new values for Width and Height. Click OK.
Step 4
If you only want to change the Boolean resolution without affecting the raster data, clear the Resample Image check box. After that, most of the dialog controls will become locked. Only those located in the Document Size group will remain active. Specify the new resolution directly in the Resolution field, or enter the desired values in the Width and Height fields. In this case, the data in the remaining fields will be dynamically updated. Clicking the OK button to apply the changes.
Step 5
Save the converted image. If you changed only the logical resolution, and the data in the original format is stored without compression, or with compression, but without loss of quality, you can overwrite the original file. To do this, press Ctrl + S. Otherwise, press Ctrl + Shift + S and save to images with a new name in any convenient format.
