By scaling, I mean that your running at 800x600 but I'm guessing your desktop (native) resolution is more like 1680x1050 or something, so the whole screen is scaled in that mode.
To see your image perfectly, you should use the native resolution, by adding this to the start of your program:
set display mode desktop width(),desktop height(),32
That will set the resolution to suit your desktop, and will get rid of all scaling. You could also use windowed mode, which I find very useful while developing, as it gives easy access to task manager etc alongside it.
Sometimes it's best not to use the ,1 flag - because it affects the textures ability to mipmap, so if it's a texture for a terrain for instance, it would probably look horrible with that ,1 flag as you'd get no filtering or mipmapping. So if the image is a texture for a 3D model, or for a particle, then don't use the ,1 flag - if it's 2D for a title screen or text or something like that, then the ,1 flag should be the best option.
SMD has a good point of course, you have all those other options for filtering, quality etc, maybe worth just checking over those to make sure it's set appropriately.
