I used IrfanView to change a JPG’s DPI from 96 to 300 as I want to print it on a bag for my child.
The new imaged created is significantly smaller 6 MB vs 682 kB. The detail summary shows the same things except for the DPI’s.
Is that possible? Is the new, smaller image usable for printing?
Answer
Did you change the pixel dimensions as well? DPI is typically meta-information to tell a printer how large to print the image. It normally doesn’t have any affect on the actual pixel dimensions of the image.
If that’s the case, than the difference is likely that you saved the image with a high JPG compression setting.
The best way for us to determine exactly what is happening is for you to post both images somewhere so we can look at them.
Attribution
Source : Link , Question Author : Kev , Answer Author : DA01