Image Resolution info from the Inkscape web site.

That link explains why I am getting images sized as if they are 90dpi rather than 72 dpi. Still doesn't tell me how to change the resolution so they are sized on the page correctly.

i must say that i do not really understand what this tutorial is for

is the OP suggesting we should use Inkscape for scaling images instead of Gimp ?
if so, why ?

importing a png image into Inkscape is not converting it into a vector

so the reason we would do this is because its seems to be easier (grabbing and dragging handles) ?

i know from experience that png images scaled in Inkscape, dont look as good as scaled in Gimp
i think i read somewhere that has to do with the scaling algorithm IS uses

also exporting images from gimp, then importing into IS and then exporting again to import again into Gimp, how complicated is that, when you can do it all in Gimp just the same ?

As you can see, the tutorial was written slightly more than 3 years ago. At that time, drastic resizing in Gimp was poor, especially if enlarging an image. Today, resizing an image in Gimp is much, much better.

Since Inkscape uses vectors, the resizing in it was smoother and more accurate.

im aware the tut is three years old
that was actually included in my initial post, but then i edited it out


images are not converted into vectors just because you import them
you need to trace an image to convert it into a vector and the result looks much different !


i see
good for us

hopefully that clears it up for daknecht as well
at least the part with scaling in Inkscape, because i still think its a bad idea

This clears up nothing at all. The issue remains the same. If there is no way of adjusting resolution of images in Inkscape then I will have to move on to other software, much as I like using open source solutions. Without that feature, Inkscape is not much use to me. You can not correctly put together figures for publication if you cannot keep full resolution image data and combine it with vector and text.

it seems there is a lot of confusion going on

from what i understand you looked for a solution to your problem and found this tutorial, which i think is actually adding to the confusion
it may have been relevant three years ago, but not today

you start with this post:

you speak of an image 7x8"
you dont tell us about the dpi, so i assume it must be 300, because you want to print it

7x8" at 300dpi = 2100x2400px

next you want to have it displayed at 2x3", which you try to achieve by changing the resolution
why do you want to change the resolution ? it has to remain at 300dpi for printing !

and whats up with the size: is the aspect ratio changed as well or is that a typo ?
if you scale down the width to 2" the height changes accordingly to 2,287", not 3"


this is a common misconception which is explained in the link Odin already gave you:
http://photo.net/learn/resize/



i really dont see the problem, images can be scaled in Gimp and you shouldnt scale anything other than vectorimages in Inkscape, because thats what it was made for

if you want to make some of your stuff in Inkscape (e.g: personally i find working with text in IS much more comfortable) use your actual Gimp-pagesize at 300dpi in the correct pixelsize for your IS document properties

lets say you want to create a page A4 for print
so you setup your canvas-size as 2480x3508px (at 300dpi !) in Gimp

do your vectorstuff in Inkscape, then export as a bitmap with the pixelsize as above (page)
resolution doesnt matter

then import that image as a layer in Gimp

I was estimating in my earlier post and tried to be more accurate in the later one. So lets take this again from the top. We will take my later numbers as that is one I am currently working on. In the current figure, I am combining 6 different images plus a line drawing graph generated in Prism into a final figure for a manuscript for publication in a scientific journal. I will be submitting it as a pdf to be printed in the hard copy journal and online as a pdf. The graph is vector line drawing data and text, and arrows and lettering (A, B, C, D, E, F) will be added to identify the 6 images. Often, not all the images are the same original size and need different resolutions to make it work, but lets leave that out. A drawing program that mixes vector graphics and bitmap images has always made this easier because it is based on a printed page size and that is the ultimate target. We want the figure to fit into a single or double column width printed page (and pdf) so it will be either 4 or 8" wide in the final output.
So now I import my 6 images into the Inkscape 8.5x11" page and each is 784x694 pixels. That has no inherent size, but viewed on a 72 dpi monitor it appears to have a physical size relative to the page ruler of 10.9 x 9.6 inches. In Canvas, I would then select the image object, go to Properties and change the Resolution to 260dpi to make it appear about 3" wide on the page. I would do the same for all 6 images and then arrange the 6 images into a 3x3 grid and label them with A, B, C.... add arrows to point out features. Then I import the line drawing graph and arrange it on the page and my figure is done and correctly sized for publication.
If I do the same in Inkscape, my images come in showing as 10.9x9.6 inches (actually slightly smaller because of the built in 90 dpi instead of 72 dpi default) and the only option seems to be to scale the images to 28% to get them to the right size relative to the page, thereby throwing away ¾ of the actual data. That is an unacceptable loss of resolution.
I could use Gimp by expanding the canvas size and bringing all the elements into the canvas and arranging them, but now because everything is a bitmap instead of individual elements on a letter sized page, arranging those elements on the canvas is challenging at best.
I hope the goal is now clear. If I am not understanding something or missing a way to do this easily in Inkscape or Gimp, please elaborate. Thanks for all the input!

if i understand everything you just posted correctly, what you want is doing all the layout in Inkscape

your page-size is 8,5x11" (=2550x3300px at 300dpi)
you have six images 784x694px (dpi unknown, i guess these images are photos)
you want to add lettering, graphs and arrows to your six images in IS

it seems to me the confusion comes from the six images of unknown resolution
you seem to think, Inkscape changes the resolution of these images automatically
depending on the rule that images should never have a lower resolution than 300dpi for print i cant really help you with your problem
you can make a vector any size you want but a rasterbased image is dependent on its pixelsize and resolution, i dont think Inkscape changes that really in any way, but im not sure

but what you could do, is do all your layout with rectangles as placeholders for your images, export as a bitmap (possibly as several layers)
import into Gimp and then import your six images and see if they fit (but that again depends on the actual resolution of your images)

Inkscape is really one good tool for resizing images. Thanks for sharing this useful conversation.