chris77 — 2011-09-11T23:15:06-04:00 — #1
Are their other units one can use on an image other than pixels? I'm haveing trouble with my images appearing in different sizes on different screen resolutions.
martinplatt — 2011-09-12T03:45:54-04:00 — #2
Ummm... Yeah, that's because the resolution is bigger or smaller. If you work in pixels or points, won't make any difference, sounds like you need to scale the images according to the difference in size compared to your original resolution? Keep it in the same aspect ratio though, or it will look strange.
Stands to reason more pixels per inch, smaller sized image.
What are you trying to do specifically?
system — 2011-09-12T06:36:42-04:00 — #3
On a given screen, a 200px x 200px image will be the same size (take up the same screen real estate) whether the image is 72ppi, 96ppi or 600ppi.
ppi is used to determine the actual print size, not screen size.
stomme_poes — 2011-09-12T09:34:29-04:00 — #4
why we use dpi, dots per inch. a pixel on my screen isn't the same physical size as a pixel on someone else's screen
this is partially why CSS "pixels" are their own thing, even: css pixels
OP: wants images to scale: you can do this, but your image is saved as pixels and browsers kinda suck at resizing, compared to an image editor.
But you can set % height and width for an image in css. Usually you'd want to set one and let the other remain "auto" so it scales in proportion.
system — 2011-09-12T19:48:13-04:00 — #5
just an fyi according to my understanding of things:
PPI (pixels per inch) and DPI (dots per inch) are not the same thing although many use them interchangeably.
ppi and dpi are both used only for determining hard copy (print) image sizes and are not used at all for sizing images for screen display. For a given screen the only thing that determines the size of an image on the screen is the overall width and height in pixels of the image.
DPI is solely a printer property and represents the number of ink dots it will lay per inch of paper in the X and Y directions. 1 DPI does not equal 1 PPI.
A general rule of thumb is you should have 300ppi minimum to make a good quality print copy which means if you want an 8" x 10" print, the original image size (and not an enlargement of an original) needs to be at least 2400px x 3000px.