Using imagecopymerge to create a translucent watermark
gd_info
GD
PHP Manual

# GD and Image Functions

## Table of Contents

- gd_info — Retrieve information about the currently installed GD library
- getimagesize — Get the size of an image
- image_type_to_extension — Get file extension for image type
- image_type_to_mime_type — Get Mime-Type for image-type returned by getimagesize, exif_read_data, exif_thumbnail, exif_imagetype
- image2wbmp — Output image to browser or file
- imagealphablending — Set the blending mode for an image
- imageantialias — Should antialias functions be used or not
- imagearc — Draws an arc
- imagechar — Draw a character horizontally
- imagecharup — Draw a character vertically
- imagecolorallocate — Allocate a color for an image
- imagecolorallocatealpha — Allocate a color for an image
- imagecolorat — Get the index of the color of a pixel
- imagecolorclosest — Get the index of the closest color to the specified color
- imagecolorclosestalpha — Get the index of the closest color to the specified color + alpha
- imagecolorclosesthwb — Get the index of the color which has the hue, white and blackness
- imagecolordeallocate — De-allocate a color for an image
- imagecolorexact — Get the index of the specified color
- imagecolorexactalpha — Get the index of the specified color + alpha
- imagecolormatch — Makes the colors of the palette version of an image more closely match the true color version
- imagecolorresolve — Get the index of the specified color or its closest possible alternative
- imagecolorresolvealpha — Get the index of the specified color + alpha or its closest possible alternative
- imagecolorset — Set the color for the specified palette index
- imagecolorsforindex — Get the colors for an index
- imagecolorstotal — Find out the number of colors in an image's palette
- imagecolortransparent — Define a color as transparent
- imageconvolution — Apply a 3x3 convolution matrix, using coefficient and offset
- imagecopy — Copy part of an image
- imagecopymerge — Copy and merge part of an image
- imagecopymergegray — Copy and merge part of an image with gray scale
- imagecopyresampled — Copy and resize part of an image with resampling
- imagecopyresized — Copy and resize part of an image
- imagecreate — Create a new palette based image
- imagecreatefromgd2 — Create a new image from GD2 file or URL
- imagecreatefromgd2part — Create a new image from a given part of GD2 file or URL
- imagecreatefromgd — Create a new image from GD file or URL
- imagecreatefromgif — Create a new image from file or URL
- imagecreatefromjpeg — Create a new image from file or URL
- imagecreatefrompng — Create a new image from file or URL
- imagecreatefromstring — Create a new image from the image stream in the string
- imagecreatefromwbmp — Create a new image from file or URL
- imagecreatefromxbm — Create a new image from file or URL
- imagecreatefromxpm — Create a new image from file or URL
- imagecreatetruecolor — Create a new true color image
- imagedashedline — Draw a dashed line
- imagedestroy — Destroy an image
- imageellipse — Draw an ellipse
- imagefill — Flood fill
- imagefilledarc — Draw a partial arc and fill it
- imagefilledellipse — Draw a filled ellipse
- imagefilledpolygon — Draw a filled polygon
- imagefilledrectangle — Draw a filled rectangle
- imagefilltoborder — Flood fill to specific color
- imagefilter — Applies a filter to an image
- imagefontheight — Get font height
- imagefontwidth — Get font width
- imageftbbox — Give the bounding box of a text using fonts via freetype2
- imagefttext — Write text to the image using fonts using FreeType 2
- imagegammacorrect — Apply a gamma correction to a GD image
- imagegd2 — Output GD2 image to browser or file
- imagegd — Output GD image to browser or file
- imagegif — Output image to browser or file
- imagegrabscreen — Captures the whole screen
- imagegrabwindow — Captures a window
- imageinterlace — Enable or disable interlace
- imageistruecolor — Finds whether an image is a truecolor image
- imagejpeg — Output image to browser or file
- imagelayereffect — Set the alpha blending flag to use the bundled libgd layering effects
- imageline — Draw a line
- imageloadfont — Load a new font
- imagepalettecopy — Copy the palette from one image to another
- imagepng — Output a PNG image to either the browser or a file
- imagepolygon — Draws a polygon
- imagepsbbox — Give the bounding box of a text rectangle using PostScript Type1 fonts
- imagepsencodefont — Change the character encoding vector of a font
- imagepsextendfont — Extend or condense a font
- imagepsfreefont — Free memory used by a PostScript Type 1 font
- imagepsloadfont — Load a PostScript Type 1 font from file
- imagepsslantfont — Slant a font
- imagepstext — Draws a text over an image using PostScript Type1 fonts
- imagerectangle — Draw a rectangle
- imagerotate — Rotate an image with a given angle
- imagesavealpha — Set the flag to save full alpha channel information (as opposed to single-color transparency) when saving PNG images
- imagesetbrush — Set the brush image for line drawing
- imagesetpixel — Set a single pixel
- imagesetstyle — Set the style for line drawing
- imagesetthickness — Set the thickness for line drawing
- imagesettile — Set the tile image for filling
- imagestring — Draw a string horizontally
- imagestringup — Draw a string vertically
- imagesx — Get image width
- imagesy — Get image height
- imagetruecolortopalette — Convert a true color image to a palette image
- imagettfbbox — Give the bounding box of a text using TrueType fonts
- imagettftext — Write text to the image using TrueType fonts
- imagetypes — Return the image types supported by this PHP build
- imagewbmp — Output image to browser or file
- imagexbm — Output XBM image to browser or file
- iptcembed — Embeds binary IPTC data into a JPEG image
- iptcparse — Parse a binary IPTC block into single tags.
- jpeg2wbmp — Convert JPEG image file to WBMP image file
- png2wbmp — Convert PNG image file to WBMP image file

Using imagecopymerge to create a translucent watermark
gd_info
GD
PHP Manual