I'm puzzled

[mig]

Playing around with pictures as I do,I came across something I find puzzling.

You have two pictures of the same dimensions,say 600x600.
Yet one is 50kb and the other 100kb.

I believe it is the picture content that makes the difference.

Can someone confirm and explain please.

 

[MidnightAngel]

Mig, I think it's the format of the pic. I know that a bitmap image is way bigger (kb speaking) than a jpeg.

 

[pipercatt]

I was once told images that have a lot of black or darker colors are larger in file size than lighter images, or ones that have white backgrounds.

 

[Fly_On_Wall]

d.p.i. dots per inch

your reselution has to do with it.

75 dpi is half the size of a 150 dpi.

also .bmp's are fucking huge compared to .jpg .tiff .gif

 

[BrassMonkey]

There are several reasons that might explain this.

1) the two pictures are in different formats (that might be a bit like asking if the computer is plugged in).

2) Some formats allow differing amount of compression. i.e. JPeg. Usually when you save a jpeg, the program will ask you the amount of compression 0-100% and you descide on the trade-off between image quality and image size.

3) Even with the same format and same compressions settings the two different images will compress to different sizes because the algorithm can make an uncomplex image smaller. Therefore a square of all white or all black will become smaller that a photo of the same size.

I hope this helps. More detail will have to come from someone else.