Ok, I have an Image in 8 bits per channel mode on Photoshop. When I try to save it doesn't let me select the A8 R8 G8 B8 option.

Why I can't do it? There's a special mode that I have to choose to make this option available?

Here's a screenshot. Only the XRGB (leading zero) it's availabe and I need the leading Alpha option.

bmp saving screenshot

Sorry for any misspelling

  • Not my area of expertise, but it's my understanding that X8 is the same other than the BMP header and A8 uses "fade to white" where X8 doesn't. Are you certain X8 is insufficient? I'm thinking this is more a questions for tech support. I can't get A8 as a selectable option for anything.
    – Scott
    Dec 16, 2014 at 19:32
  • I don't really know why it's needed A8. The software that I use to make games, proccess some specific textures in BMP with this specific header so I don't really know what to do.
    – Joe
    Dec 16, 2014 at 19:57

2 Answers 2


You can't select ARGB because there's no alpha channel in your document. ARGB requires an actual, for real alpha channel.

I'm not sure why your application requires it, but a simple way to make that selection available is to add an empty alpha channel, or select a layer and save the selection (which creates an alpha channel).

  • It was so simple. I'm dissapointed with miself hahaha. Thank you so much!
    – Joe
    Dec 17, 2014 at 17:27
  • To be fair, it's not exactly spelled out in the UI, and you would have a hard time finding it in the Help docs, I suspect, although the information is probably in there somewhere. Dec 17, 2014 at 19:27

I tried to make the texture with the software that makes the textures and now it works. I still not know how can I make the headers available in photoshop by the way but I'll mark this as answered.

PS: I'll mark this answer as the solution in 2 days if no one can give me a solution. Thanks for everything.

  • Good to hear you fixed it, but can you please add some more information to your answer before you accept it? As it is, it doesn't really look like it solves the problem!
    – Yisela
    Dec 17, 2014 at 11:12
  • I've just generated the image with that headers in World Machine (A terrain generator software). I didn't know that would be possible, after reading the manual I realized that.
    – Joe
    Dec 17, 2014 at 17:30

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