pic file sizes increase when elements 4 opens them???

[demonweb]

so i check the file size of a jpeg on my desktop- windows properties tells me it's 4.3 MB in size.

then i open the pic in elements 4 and select the "save for web" option. the pic opens there and elements tells me the file size is 77M!

so i check every pic on my desktop, and then in elements 4, and every single time, the picture file size is tremendously larger in elements than in windows properties. shouldn't they be the same? what's going on here- can anyone explain this please?

[Wendy]

Hi there ....

... and welcome to the forum :)

When you save a file (say as a jpg) it gets compressed and when you look at them on your desktop you see the size of the compressed file.

Wendy

[demonweb]

hi and thanks for the reply.

however, i still honestly don't understand because that means a 77 meg pic was compressed down to 4.3 megs? i don't know enough about compression, so i'll have to research and learn more i guess. but that still sounds like a lot of compression to me.

[Ward Grant]

I knew I had seen a similar discussion recently, but it took me awhile to find it. This thread may shine some light on the subject.
Ward


http://www.photoshopelementsuser.com/forum/showthread.php?t=5577&highlight=%22file+dimensions%22

[TonyW]

Thanks Ward for reminding me where I saw that before. I remember now I did the simple experiment of creating a blank white document 1000x1000 pixels in RGB color. Elements assumes that every pixel could have a different color so takes about 3 bytes to describe each pixel - so it says it will need 3x1000x1000 or 3MB to store it. When you save it as a jpeg it saves space by saying that all it needs to know is that there are 1000x1000 pixels and they are all the same color and it only takes 3KB to describe it - a very efficient 1000 to 1 compression. Draw something on the document and the Elements document size doesn't change but the jpeg file gets bigger - the more complex the drawing the bigger the jpeg file gets.

Tony