Photoshop Image Resizing
These are instructions for Adobe Photoshop version 5.5. The procedures are similar in 6.0 and 7.0
First, run Photoshop
and then open your Image.
Select the "File" menu,
and then "Open"
Once the file is open you will want to resize it.
Select the "Image" menu
and then select the "Image Size" option
A new dialog will open:
Notice that this shows the image size in pixels ("Pixel Dimensions")and it's corresponding DPI settings ("Resolution").
You will want to place a new DPI number (300 is recommended) into the proper field
as shown below, and make sure both "Constrain Proportions" and "Resample Image" are checked.
The Pixel numbers should increase proportionately to the DPI number you have input.(red arrows point to the pixel sizes)
If you only want to change just the DPI information in the image, and not proportionally scale the picture to a larger size, make sure the "Resample Image" checkbox (outlined in red above) is unchecked!
After you have made all size / DPI adjustments, you will want to save the modified image. Select the "File" menu, and then "Save As". A new dialog will open:
change the "Save As" entry at the bottom to JPEG (the file format), and change the file's name (don't overwrite the original, keep it as a backup!).
Once you press "Save", another dialog will pop up, this time JPEG compression options:
compression samples and explanation
Once you have saved the Image to a new file, you are done!
Usually it is a good idea to compress as much as possible without losing *visible* image quality.
Since JPEG is a "lossy" format, you may want to make some tests on your own to determine the best ratio for the *particular* Image.
See our page with Image Compression samples.
Some good JPEG numbers to aim for in Photoshop:
7-9 on Quality
File size of *at most* 200-250k (kilobytes)
Also see the size & cropping page
Any more questions? Ask the Guru directly!
