why do my .pngs have grey boxes around them on some computers?

On certain computers my game has grey boxes around it's images and im not sure why. When i exported them i had a grey background but that doesn't explain why it only shows up on certain computers.

Does it matter if i have one of these options checked when i export an image to save as png:

- interlaced

- smooth

- dither solid colors

or maybe its the resolution setting? if u had this problem or know why this is happening i'd appreciate the help. it's not reaaaaaaaally annoying but im a perfectionist.

Those computers' video card is set to display 16 bit color ( I'm pretty sure )

That will do it almost every time. On displays/cards using true/32 bit/whatever they call it, color it won't happen.

Is that PNG's or all image files? And is there away around this?

the problem that your art won´t look the same on machines with lower color range setting is not png specific,it can happen with all media file types if they use color values out of the scope of a color setting on the user machine.
The problem is just even way more noticable for pngs (speaking of high-spec png32 now) as its the format really allowing use of the full 32 bit color palette plus various alpha value shades for images.
So its rather sure that if you use a png32 with lots of colors and maybe a nice alpha fade there,too,it will look really awkward on machines with low color range setting.
Its good to keep simple restrictions,meaning for example using gifs where it makes sense (also good regarding getting lower filesize) but if you´d focus on having graphics looking fine on the oldest machine setups,you could aswell use really limited gifs only using a websafe palette.(And other than for retro touch pixel art games that would look sucky in most cases).

Yep,

PNG use 24 bit to create a smooth mask (transparency)
A GIF will use 8 bit for the mask, hence the "pixilated" look of it

I have noticed as well differences when using gifs (your kinda grey effect) on 16bit video cards.

Can't please everyone :D

hmm. thanks for the info

Yea thanks guys.