imagecreatefromstring

imagecreatefromstring is a function in PHP's GD library that creates a new image resource from binary image data contained in a string. It analyzes the string to detect the image format and decodes it into an in-memory image resource that can be manipulated with GD functions. The supported formats typically include GIF, JPEG, PNG, and WBMP, depending on how PHP was built with the corresponding decoders.

Syntax: resource imagecreatefromstring(string $image) Returns an image resource on success or false on failure.

Return value and behavior: On success, it returns a GD image resource that can be used with other GD functions such as imagejpeg, imagepng, or imagegif. On failure, it returns false, for example if the string does not contain valid image data or if the necessary decoders are not available. The function reads the image data from memory, so it is convenient when image data comes from sources other than the local filesystem, such as a database, a network response, or a string generated at runtime.

Usage considerations: Since the image data is loaded entirely into memory, large images can consume substantial PHP memory. It is often advisable to validate data size and handle potential errors gracefully. In environments where the image format is uncertain, the function’s return value should be checked before proceeding with further image processing.

Example: $data = file_get_contents('photo.png'); $img = imagecreatefromstring($data); if ($img === false) { // handle error } // proceed to manipulate or save the image

See also: imagecreatefromgif, imagecreatefromjpeg, imagecreatefrompng, getimagesize.