Resize image file based on img width/height

ericpode

I have a bit of a problem getting a user to resize their images before adding them to the web page. This can sometimes end up with a large image file embedded in an img tage which has much smaller width and height parameters.

It struck me that it might be useful to have a script that he would run on the server after uploading changed pages. The script would go through all of the pages on the site and find each occurance of an img tag and its width and height parameters, and then query the corresponding image files on the server to find out what their true dimensions were. Whenever the true dimensions are different to the img tag's height and width values then GD (or something) would be called to resample the image file down in size so that it agreed with the values in the img tag. This new downsized image file would then replace the old oversized image file. If the image file dimensions already agreed with the img values then we skip that image file.

I'm not sure about CSS so perhaps the script might need to parse image files and sizes in styles too.

Does anyone know if such a script exists, or perhaps a better way of handling this problem.

TF_TheMoon

Are your users uploading the images and the pages together or are they simply uploading ther images which are then dynamically added to the pages?

ericpode

The pages (or at least the changed parts) would be static text with images inserted (img tags) - no dynamic stuff. I'm just starting to learn CSS, so I'm not sure if there may also be images embedded in css file aswell.

Having done a lot of Google searching for a solution to this, it seems that most people want to do the opposite (dynamically generate img width and height values from the actual sizes in the image file), whereas I want to resize the image files on the server to agree with the img width and height values (no changes to the html/php files). I'm not sure if PHP or maybe a perl script would be more appropriate to do this.

I guess there may be one or two minor complications such as an image file used more than once with different image width and height values - so which do you choose?

If people are in the habit of resizing images on a WYSYWIG page editor by dragging the corners, you would have thought that the editor would automatically re-size the image file on uploading.

TF_TheMoon

WYSIWYG editors purely manipulate HTML, they dno't touch the images, if they did you'd have all kinds of problems.

You can do it with PHP, the problem is that if people resize the images through WYSIWYG editors they may distort the ratio, but if that is fine for what you want, then you can certainly do that.

There are a few image libaries that allow you to re-size images, the most common use is to create thumbnails or apply watermarking.

I find this one quiet useful http://www.fullo.net/progetti/smartthumb/index.php?source=class
Its a modified version of one, I've enchanced it further myself, but I don't have access to the source from here.

That would allow you to resize the individual images. You'd then need to write a script to read through your pages, find the img tags, read the height and width parameters, take the scr location, open the image get the sizes, compare, if its different then you coudl use that class to ersize them.

If the WYSIWYG editor is on a web page of yours, and you parse the contents to then save it as a file, you coudl build it into that script to check and resize the images during the save