Pixels and dimensions
A digital picture is made of tiny squares called pixels. The dimensions are how many pixels wide and tall it is, for example 1200 x 1800 pixels. More pixels mean more detail.
File size
File size is how much storage the file takes, measured in KB or MB. It depends on the dimensions, the format and how much the file is compressed. A larger picture usually has a larger file size, but compression can make it much smaller.
Resolution and DPI
Resolution, often written as DPI or PPI, describes how many pixels are used per inch when a picture is printed. It matters for print, not for screens. A picture of 1200 x 1800 pixels printed at 300 DPI is 4 x 6 inches, because 1200 divided by 300 is 4 and 1800 divided by 300 is 6.
Which one should you change?
- A form says the photo must be an exact size in pixels: change the dimensions.
- A form says the file must be under a number of KB: change the file size by compressing.
- You are printing: check the dimensions and the DPI you need.
Read more about shrinking files in how to reduce image size in KB.
Why use PicFitter
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