Pixel resolution and all that Stuff


TPF Noob!
Dec 27, 2015
Reaction score
Can others edit my Photos
Photos OK to edit
Hello I have just joined and a happy new year to all.

I am trying to learn about pixel and have been experimenting. here are my two difficulties.

1. trying to get a picture with a certain resolution on screen, I tried Gimp but it seems to provide its own resolution. I do not have Photoshop. Is there a way to display a picture without "outside" interference please

2. Trying to scan a picture in Epson scan by eg 300 x 200 but it only shows one dimension.

I have a feeling that I am going about this all the wrong way, could you please sort me out.

One other thing, this is all new to me. How do I go to New Threads, I only came about this by clicking about and do not know how to get here again.


Open a photo in GIMP and from the Image menu select Scale Image. In the Scale Image dialog you'll see values for both Image Size as Width and Height as well as X, Y resolution.

You can change the X, Y resolution values to whatever you want as often as you like and the photo's Width and Height values will remain unchanged -- changing those resolution values does not actually change the size of the photo because the resolution values are pixels per inch. If you change the value then GIMP (or PS or whatever) simply recalculates the inch value. In other words the same physical size photo will make either a 100 ppi print 30 inches wide or a 300 ppi print 10 inches wide. 100 x 30 = 3000 and 300 x 10 = 3000. That photo would be 3000 pixels wide either way.

If on the other hand you change either the Width or Height values you are actually changing the photo and either removing pixels or making up new ones to add in.

The scanner should likewise show you both resolution values as well as width x height values. In the case of the scanner what you're scanning (photo or film) does in fact have a real size that the scanner measures. Say you're scanning a print that is 4 x 6 inches. The scanner knows the print is 4 x 6 inches and so when you enter a resolution value like 200 ppi the scanner will calculate the width and height and scan the photo at that size (200 x 6 = 1200 pixels wide).

"2. Trying to scan a picture in Epson scan by eg 300 x 200 but it only shows one dimension."

If you think about how the scanner works then setting the PPI in one dimension makes sense. It starts on the left edge and looks at a spot, saves a data bit to say what it saw and then moves to the next spot. The number of spots it looks at in an inch is set by the PPI (pixels per inch) that you specify. If the picture to be scanned is 3 inches across and you set PPI to 100 then you'll get a scan that's 300 pixels across. Same going down the page. If you want a result that's 300X200 then set PPI to 100 and scan a picture that's 3 inches wide and 2 inches tall..........
For the second part to your question:
If you hover over the down arrow next to your user name (top right of screen) and then select "Your Content", it will show all of your recent activity on the forum.

Also when you are in a thread, you can see what forum category it can be found in by looking here:

You can also change your preferences to be notified when there is some activity to a thread you are "watching".
Click on "Preferences":

... then in the options check one or both of these.


Or just go through the forum categories (Photography Forum) and look under each entry to see from the date stamp if something new has been added
Last edited:
You might try Irfanview instead of GIMP which is free and can be downloaded online. Download the add-ons as well, also free.
Thank you everyone, I have some work to do now experimenting with your advice.

Best to all


Most reactions

New Topics