The difference is that PNG uses an alpha channel for transparencies while GIF just sets a certain (and single) color to be transparent. GD just seems to ignore the alpha channel in a PNG file so when a pixel is (0,0,0,0), it just reads the first 3 value which result in a black pixel.

Do you know another module for manipulating images? Besides ImageMagick that is.

In reply to Re^8: Resizing images with transparent background? by aweizd
in thread Resizing images with transparent background? by Anonymous Monk

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