My guess is that this is because of the interpolation when resampling. Makes it less easily compressable. (Notice the 'anti-aliased' edges in the resized picture?)

Marco Wessel

On Wed, 4 Jun 2003, Daniel Carrera wrote:

Hi,

This is really weird. I have a PNG image. I tried to make it smaller by resizing it down, but instead it got BIGGER. I don't understand this at all.

I put the images on the web:

Original: http://www.math.umd.edu/~dcarrera/screenshot.png Resized: http://www.math.umd.edu/~dcarrera/screenshot_resized.png

With width and height of the resized image are 0.8 times the size of the original, so I would have imagined that the resized image would be 0.8*0.8 = 0.64 times the size of the original, but that's not the case:

$ du -sk * 52 screenshot.png
128 screenshot_resized.png

The new image is over 4 times bigger than the original!

These are RGB images BTW, but that shouldn't cause this.

Does anyone know what's happening?

--- Daniel Carrera wrote:

On Thu, Jun 05, 2003 at 02:12:22AM +0200, Marco Wessel wrote:

My guess is that this is because of the interpolation when resampling. Makes it less easily compressable. (Notice the 'anti-aliased' edges in the resized picture?)

Marco Wessel

Any suggestion as to how to fix it?

Retake the screenshot, after reducing the size of the window. Really. Resizing without anti-aliasing is like cutting 1 pixel slivers out of the image, and can make vertical or horizontal lines disappear out of the image.

At 52Kb, the image size is satisfactory for broadband/LAN users. If the image is to be used on the web, why not consider using the image size attributes of HTML to automatically rescale the image?

http://www.w3.org/TR/html4/struct/objects.html#h-13.2 http://www.w3.org/TR/html4/struct/objects.html#visual

You could also reduce the colour depth without any noticable drop in quality. Applications usually keep to a 256 colour default pallet.

Magic bullets not found here.

Jonathan Paton

===== #!perl
$J=' 'x25 ;for (qq< 1+10 9+14 5-10 50-9 7+13 2-18 6+13 17+6 02+1 2-10 00+4 00+8 3-13 3+12 01-5 2-10 01+1 03+4 00+4 00+8 1-21 01+1 00+5 01-7 >=~/ \S\S \S\S /gx) {m/( \d+) (.+) /x,, vec$ J,$p +=$2 ,8,= $c+= +$1} warn $J,,

___

Hi,

Daniel Carrera writes:

This is really weird. I have a PNG image. I tried to make it smaller by resizing it down, but instead it got BIGGER. I don't understand this at all.

I put the images on the web:

Original: http://www.math.umd.edu/~dcarrera/screenshot.png Resized: http://www.math.umd.edu/~dcarrera/screenshot_resized.png

With width and height of the resized image are 0.8 times the size of the original, so I would have imagined that the resized image would be 0.8*0.8 = 0.64 times the size of the original, but that's not the case:

$ du -sk * 52 screenshot.png
128 screenshot_resized.png

The new image is over 4 times bigger than the original!

128 / 52 = 2.46

These are RGB images BTW, but that shouldn't cause this.

Actually these are RGBA images. If you want to reduce the file size, you'd better flatten the image since I don't see any alpha information.

Sven

Hi,

Daniel Carrera writes:

Thanks. I didn't realize that they were. How do you tell appart an RGBA image from an RGB image? Gimp calls them both "RGB".

I used "file foo.png" but there are lots of indicators in GIMP as well. The most obvious is probably if you can Flatten the image or not.

Sven