Upload merged Images and then break apart with PHP

Question

Looking for a way to enable someone to upload a single file which will be series of image files (all gif) merged together as one big file. Here is what I need to do:

1. Using VB6, want to merge the image files (potentially dozens of them) into a single file
2. Upload file to a PHP Script (easy enough)
3. Have PHP break apart the single file and write image files

I know how to handle the uploading of the file. I also know how to write the image files in PHP. What I am unsure of is the merging/un-merging operation.

In theory, I should just be able to use VB6 to merge all images using binary read/writing. However, does anyone know the series of binary codes that prefix each .gif file so PHP can pick up on that, or do I need to write some sort of binary separator in between each merged image?

I could surely tinker with this myself, but I thought some of you smarter-than-me coders may have already done this, and/or could provide a link, some code, or some 'things to consider'.

Thanks.

Answer 1

Instead of merging/un-merging, if the whole purpose is to avoid overhead of sending dozens of files, why not zipping them and unzipping in PHP?

That should be far easier than the merging operation you're proposing.

Answer 2

• Here's a free Zip/Unzip library for Windows: Info-ZIP
• Here's some sample code that uses Info-ZIP: Zip and Unzip Using VB5 or VB6
• Here's PHP's documentation on the ZIP module: php.net/zip
• Here's an example of how to use "unzip" command through PHP, rather than using the Zip module: Zipping and Unzipping Files with PHP

Google is your friend :)