Zip file information please

[Roger GSA]

I recently wanted to send some photographs via email so I created a Zip file of the .jpg images.

I was surprised to see the original and the zip file were the same size. Is that because a .jpg image is already compressed and cannot be reduced further?

Just curious can any one advise me please.

Roger

 

[cookie]

I was surprised to see the original and the zip file were the same size. Is that because a .jpg image is already compressed and cannot be reduced further?

yes, it is.

 

[Womble]

That's exactly right. JPG files are already compressed (try saving the same file as a BMP and you will see the difference with the size of an uncompressed bitmap file).

The zip compression process will rarely make the photos any smaller, in fact the packing process tends to make them just a little larger, but packing several pictures into one zip file will make them easier to send, so it can still be worth doing.

 

[Roger GSA]

Guys, many thanks for your swift response.