Add support for other bit depth for imagecreatefrombmp

[hoit]

Description

Hello,

In my application, i need to load different kind of bitmaps to apply some checks on it.
I see that imagecreatefrombmp works correctly for bitmap file which have indexed color with 8 bit depth only.

The function return false if the image is :

• not in indexed color mode
• in index color mode with 4 bpp (16 colors).

I saw that some libs are able to manage it or found some pieces of code to do it but it would be great to add it natively !

Is it possible ?
Thanks in advance

[hoit]

I think it is more a bug than a feature request.

You can reproduce the issue by loading this bitmap file :
summer_and_spring_items.zip

I mention than i downloaded the pack here and converted the png to bitmap : https://butterymilk.itch.io/tiny-wonder-forest
The issue is also probably linked with this one i opened : #11442

Here is my php version :

PHP 8.1.2-1ubuntu2.11 (cli) (built: Feb 22 2023 22:56:18) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.1.2, Copyright (c) Zend Technologies
    with Zend OPcache v8.1.2-1ubuntu2.11, Copyright (c), by Zend Technologies

PHP Version

8.1.2

Operating System

Ubuntu 22.04.2 LTS