ICO files and BMP files

[Alain Dekker]

One advantage of ICO files is that they support multiple image sizes in a
single file. Combined with a specific colour palette, they offer a more
compact way of storing image resources for your project.

However, there are downsides. They are more tricky to edit and due to the
specific colour palette (and unless you're an expert at manipulating these
files) generating a new ICO file can be tricky.

My question is this:
* You only had one image size to support, say 64x64
* You are not overly concerned with the small additional disk space
requirement (about 13kB for a BMP compared with 6kB for the ICO)
Are there any disadvantages with converting my project resources to a BMP,
24-bit version? Is there anything in the ICO file that is NOT captured by
converting it into a 24-bit BMP?

The advantages to me are ease of creating new and editing existing images.
Specifically not having to worry about colour palettes all the time for
these very small files is a big bonus. But I don't want to throw away all
these existing ICO files unless I'm sure its ok to do it.

Thanks,
Alain

 

[Alain Dekker]

Thanks for that advise, Peter. I'm not too familiar with the PNG format but
having been prompted by your reply I've read about the lossless compression
benefits of PNG (over BMP). Generally, PNG is very highly regarded. Support
for PNG, while a much newer format than BMP, is very much commonplace now,
so I'll take your advice (with thanks!) and go with that.

Thanks,
Alain

[...]
My question is this:
* You only had one image size to support, say 64x64
* You are not overly concerned with the small additional disk space
requirement (about 13kB for a BMP compared with 6kB for the ICO)
Are there any disadvantages with converting my project resources to a
BMP,
24-bit version? Is there anything in the ICO file that is NOT captured by
converting it into a 24-bit BMP?

.ico resources inherently support the multiple resolutions/formats, of
course. They also include a transparency mask; this can be handled in
.bmp (and other formats) through the use of an alpha channel, but 24 bpp
formats don't usually include alpha (the most common alpha-supporting
formats are the 32 bpp formats).

But there benefits are moot when using the image in a context that doesn't
take advantage of these, or can be achieved some other way.

It sounds to me as though you don't need the specific benefits of the .ico
format, and plain bitmap files would suffice. However, I would not use
.bmp as the format. Instead, I would use .png. It's uses a lossless
compression as .gif does, but allows pixel depths greater than 8 bpp.

Pete