The getimagesize() function will
determine the size of any GIF,
JPG,
PNG, SWF, SWC, PSD, TIFF, BMP
or IFF image file and return the
dimensions along with the file type and a height/width text
string to be used inside a normal
HTML IMG tag.
Returns an array with 4 elements. Index 0 contains the
width of the image in pixels. Index 1 contains the height.
Index 2 is a flag indicating the type of the image: 1 = GIF,
2 = JPG, 3 = PNG, 4 = SWF, 5 = PSD, 6 = BMP, 7 = TIFF(intel
byte order), 8 = TIFF(motorola byte order), 9 = JPC, 10 =
JP2, 11 = JPX, 12 = JB2, 13 = SWC, 14 = IFF. These values
correspond to the IMAGETYPE constants that were added in PHP
4.3. Index 3 is a text string with the correct height="yyy"
width="xxx" string that can be used directly in an IMG
tag.
With JPG images, two extra
indexes are returned: channels and
bits.
channels will be 3 for RGB pictures and 4 for CMYK
pictures. bits is the number of bits
for each color.
Beginning with PHP 4.3, bits
and channels are present for other
image types, too. However, the presence of these values can
be a bit confusing. As an example,
GIF always uses 3 channels per pixel, but the number
of bits per pixel cannot be calculated for an animated GIF with a global color table.
Some formats may contain no image or may contain
multiple images. In these cases,
getimagesize() might not be able to properly determine
the image size. getimagesize() will
return zero for width and height in these cases.
Beginning with PHP 4.3,
getimagesize() also returns an additional parameter, mime, that corresponds with the MIME
type of the image. This information can be used to deliver
images with correct HTTP Content-type headers:
If accessing the
filename image is impossible, or if it isn't a valid
picture, getimagesize() will return
FALSE and generate a
warning.
The optional imageinfo
parameter allows you to extract some extended information
from the image file. Currently, this will return the
different JPG APP markers as an
associative array. Some programs use these APP markers to
embed text information in images. A very common one is to
embed IPTC http://www.iptc.org/
information in the APP13 marker. You can use the
iptcparse() function to parse the binary APP13 marker
into something readable.
注: TIFF support was added in PHP 4.2.
This function does not require the GD image library.
See also image_type_to_mime_type(), exif_imagetype(), exif_read_data() and exif_thumbnail().
URL support was added in PHP 4.0.5.