OpenGL Problem Alpha Channel


I have a problem with OpenGL, I use it because it’s really fast!

I’d like to do an animation, so I click on the OpenGL video icon and it renders every frame on a folder.
But if I render a single frame with OpenGL camera icon then I save the picture, there’s no “artifact”, I know this artifact are caused by alpha channel.
Though, I’m always exporting to .JPG which doesn’t support alpha…

I changed every textures in the Blender Game mode to “Alpha Clip”.

Look at the difference

To me, it seems OpenGL animation (video icon) save the image with color channels and alpha transparency… And I want it to only draw RGB colors.