Determine dimensions of graphic image

[Al_Link]

Is there a way to determine the dimensions of a JPG or GIF image file? I'm trying to generage html code to display an image and I want to use the exact height and width specs.

[jnuneznyc]

GetImageSize generates an array() with 4 values for any of the following images: GIF, JPG, PNG, SWF, SWC, PSD, TIFF, BMP, IFF

Value 0 = width
Value 1 = height
Value 2 = type
Value 3 = width and height for HTML IMG tags

<?php
    $size = GetImageSize ("images/a.jpg");
?>

View the docs at PHP GetImageSize() for more information

[jpmoriarty]

is there a way it can be used with a dynamically generated image by any chance? i use a php script to do my thumbs quite a bit, so obviously my img tags has the php page in it <img src="thumbs.php?file=xx.jpg"> and it creates the thumb of the file i pass to it. is there some way i can run something first that will work out the dimensions of the thumb before i call it for real, so that i can include the height and width commands too?

ie can i call get_image_size() on a php page?

[jnuneznyc]

I don't think so... Best thing to do is write a function that will create a thumbnail for the image and return the filename and size so it can be placed into the img tag. Also will prevent the thumbnail from being generated every time it is requested.

Best way to cache thumbnails is to compare the file dates

If thumbnaildate >= originalpicdate then
    pass image thru
elseif thumbnaildate <= originalpicdate then
   generate new thumbnail