In case anyone is wondering what these filters are for, have a look at the W3C's specification:
http://www.w3.org/TR/PNG-Filters.htmlBuradaki sabitler bu eklenti için tanımlanmış olup, sadece eklentinin PHP içinde derlenmiş olması veya çalışma anında dinamik olarak yüklenmesi halinde kullanılabilir.
GD_VERSION
    (string)
   GD_MAJOR_VERSION
    (int)
   GD_MINOR_VERSION
    (int)
   GD_RELEASE_VERSION
    (int)
   GD_EXTRA_VERSION
    (string)
   GD_BUNDLED
    (int)
   IMG_AVIF
    (int)
   IMG_BMP
    (int)
   IMG_GIF
    (int)
   IMG_JPG
    (int)
   IMG_JPEG
    (int)
   Bilginize:
Bu sabit
IMG_JPGile aynı değere sehiptir.
IMG_PNG
    (int)
   IMG_TGA
    (int)
   IMG_WBMP
    (int)
   IMG_XPM
    (int)
   IMG_WEBP
    (int)
   IMG_WEBP_LOSSLESS
    (int)
   IMG_COLOR_TILED
    (int)
   IMG_COLOR_STYLED
    (int)
   IMG_COLOR_BRUSHED
    (int)
   IMG_COLOR_STYLEDBRUSHED
    (int)
   IMG_COLOR_TRANSPARENT
    (int)
   IMG_AFFINE_TRANSLATE
    (int)
   IMG_AFFINE_SCALE
    (int)
   IMG_AFFINE_ROTATE
    (int)
   IMG_AFFINE_SHEAR_HORIZONTAL
    (int)
   IMG_AFFINE_SHEAR_VERTICAL
    (int)
   IMG_ARC_ROUNDED
    (int)
   Bilginize:
Bu sabit
IMG_ARC_PIEile aynı değere sahiptir.
IMG_ARC_PIE
    (int)
   IMG_ARC_CHORD
    (int)
   IMG_ARC_NOFILL
    (int)
   IMG_ARC_EDGED
    (int)
   IMG_GD2_RAW
    (int)
   IMG_GD2_COMPRESSED
    (int)
   IMG_EFFECT_REPLACE
    (int)
   IMG_EFFECT_ALPHABLEND
    (int)
   IMG_EFFECT_NORMAL
    (int)
   IMG_EFFECT_OVERLAY
    (int)
   IMG_EFFECT_MULTIPLY
    (int)
   IMG_FILTER_NEGATE
    (int)
   IMG_FILTER_GRAYSCALE
    (int)
   IMG_FILTER_BRIGHTNESS
    (int)
   IMG_FILTER_CONTRAST
    (int)
   IMG_FILTER_COLORIZE
    (int)
   IMG_FILTER_EDGEDETECT
    (int)
   IMG_FILTER_GAUSSIAN_BLUR
    (int)
   IMG_FILTER_SELECTIVE_BLUR
    (int)
   IMG_FILTER_EMBOSS
    (int)
   IMG_FILTER_MEAN_REMOVAL
    (int)
   IMG_FILTER_SMOOTH
    (int)
   IMG_FILTER_PIXELATE
    (int)
   IMG_FILTER_SCATTER
    (int)
   IMAGETYPE_GIF
    (int)
   IMAGETYPE_JPEG
    (int)
   IMAGETYPE_JPEG2000
    (int)
   IMAGETYPE_PNG
    (int)
   IMAGETYPE_SWF
    (int)
   IMAGETYPE_PSD
    (int)
   IMAGETYPE_BMP
    (int)
   IMAGETYPE_WBMP
    (int)
   IMAGETYPE_XBM
    (int)
   IMAGETYPE_TIFF_II
    (int)
   IMAGETYPE_TIFF_MM
    (int)
   IMAGETYPE_IFF
    (int)
   IMAGETYPE_JB2
    (int)
   IMAGETYPE_JPC
    (int)
   IMAGETYPE_JP2
    (int)
   IMAGETYPE_JPX
    (int)
   IMAGETYPE_SWC
    (int)
   IMAGETYPE_ICO
    (int)
   IMAGETYPE_WEBP
    (int)
   IMAGETYPE_AVIF
    (int)
   IMAGETYPE_UNKNOWN
    (int)
   IMAGETYPE_COUNT
    (int)
   PNG_NO_FILTER
    (int)
   PNG_FILTER_NONE
    (int)
   PNG_FILTER_SUB
    (int)
   PNG_FILTER_UP
    (int)
   PNG_FILTER_AVG
    (int)
   PNG_FILTER_PAETH
    (int)
   PNG_ALL_FILTERS
    (int)
   IMG_FLIP_VERTICAL
    (int)
   IMG_FLIP_HORIZONTAL
    (int)
   IMG_FLIP_BOTH
    (int)
   IMG_BELL
    (int)
   IMG_BESSEL
    (int)
   IMG_BILINEAR_FIXED
    (int)
   IMG_BICUBIC
    (int)
   IMG_BICUBIC_FIXED
    (int)
   IMG_BLACKMAN
    (int)
   IMG_BOX
    (int)
   IMG_BSPLINE
    (int)
   IMG_CATMULLROM
    (int)
   IMG_GAUSSIAN
    (int)
   IMG_GENERALIZED_CUBIC
    (int)
   IMG_HERMITE
    (int)
   IMG_HAMMING
    (int)
   IMG_HANNING
    (int)
   IMG_MITCHELL
    (int)
   IMG_POWER
    (int)
   IMG_QUADRATIC
    (int)
   IMG_SINC
    (int)
   IMG_NEAREST_NEIGHBOUR
    (int)
   IMG_WEIGHTED4
    (int)
   IMG_TRIANGLE
    (int)
   IMG_CROP_BLACK
    (int)
   IMG_CROP_DEFAULT
    (int)
   IMG_CROP_TRANSPARENT ile aynı.
     PHP 7.4.0 öncesinde, Görüntünün şeffaf rengi yoksa, paketlenmiş libgd
     IMG_CROP_SIDES'a geri düşer.
    
   IMG_CROP_SIDES
    (int)
   IMG_CROP_THRESHOLD
    (int)
   eşik ve renk ile
     belirtilen görüntüyü kullanarak kırpar.
    
   IMG_CROP_TRANSPARENT
    (int)
   IMG_CROP_WHITE
    (int)
   In case anyone is wondering what these filters are for, have a look at the W3C's specification:
http://www.w3.org/TR/PNG-Filters.html