...OK....with you so far...
...and thats where you lose me.
Why?
What do you mean by 'e-mail a LOT larger'?
How are you making these images 'larger'?
You then go on to say...
No, not really.
You start by saying you have to 'e-mail' images bigger than 4x6.....this doesn't make sense....digital images have no linear size, only pixels.
You then go on to say that the image has to be 800x600....OK, thats more like it, that makes more sense, but why is 800x600 a 'LOT' bigger than what you had before?
What size was the image originally if 800x600 is a 'LOT' bigger?
800x600 is tiny by todays standards.
You see why it doesn't add up?
Lets take your 800x600 example though...
If you give that image a 'resolution' of 300ppi you would get a print 2.6" x 2".
To get a PRINT 4" x 6" you would first have to crop it to the right ratio.
800x600 is not the same ratio as 4x6.
The image would need to be 800x533px (taking the longest side as unchanged)
Then you would have to do one of two things...
1. Keep the resolution constant and INCREASE the number of pixels in the image.
2. Keep the number of pixels constant and DECREASE the resolution.
Option 1 would therefore need an image 1200x1800px.
Option 2 would therefore need a resolution of 133.3
Regards.
MrTom.
