Rhia474: I am not sure as late I do not have much time for rendering, BUT since P12 release I have heard tidbits about the render engines so I took it that is why they say opening older scenes you have to do some tweaking of materials...don't know about going backwards as I have not explored.
Now, for your image - when you set the Dimensions and the Dpi, in your Image Editor (any one, I don't know why JoEtzold gets a different reading in PhotoImpact as I do not, ALL my editors read all files as they are saved) - now, for yours; is the Pixel Dimension (height and width) still the same values as you input in Poser?

In my last samples above: Note how #1 and #4 have the Same 'Pixel Dimension' (the top values). This is Size in digital space. The 'Document Size' and 'Dpi' will be the Resolution within the Print Space on a sheet of paper. 

For my Printing I first created a Blank picture in PhotoShop, then I set my desired Resolution and Document Size and took note of the Pixel Dimension as my Image Editor calculated it - (with Resampling ON) if I change the Dpi it changes the Pixel Dimensions.
Not sure if perhaps this the "correct" way to go but to my I was Reverse Engineering so I could tell Poser what I wanted.

Now for yours, they blurry, I am guessing it may be a Render Engine issue? One Engine rendering your textures different then the other?? Not being a Poser engineer nor having the files to recreate and experiment....I am only guessing.
But check your Render in the Image Editor, see if the Pixel Dimension is as you input into Poser.

@JoEtzold; I don't know why your Image Editors do what they do. All mine (both paid and free) will always open any image up in what ever it was saved in even when I take it into a different editor - I often take my Photos as well as Renders into multiple editors to take advantage of what each has to offer.
Example: I generally begin with a photo in PhotoShop, from there I also have access to Topaz Labs filters, then I may save it and open it in On1 and do further editing, then perhaps into Affinity Photo, then back into PhotoShop - at ALL Times if it is a 180dpi photo it remains 180dpi when I reopen it. If it is a 300dpi it remains 300dpi
In ALL my Image Editing I NEVER reduce to 72dpi until the LAST step and only if I am posting to the Web. If I intend to Print it REMAINS at (generally) 200-300dpi whichever I DECIDE to do with it.

Now, there are few exceptions such as On1, that one likes to Upscale and often to an image property that I have to reduce or flatten to further work with in PhotoShop.
But still I have NO Image Program that will alter my Document Settings (page size nor Resolution) when going from one to the other.

Here are four Photos, all JPGs, all taken from Different devices, the top left being a still shot snapped from my Cannon video recorder, others from my camera, my wife's camera, and my Cannon camera.
Each device takes photos (JPG) with their manufactured Size and Resolution determined by the makers.
ALL of these four photos I ONLY OPENED in Photoshop - NO change was made to any of them - I just opened the photo and pulled up the Size via the Edit tab at the top, made NO CHANGES to ANY VALUES.
Note how each photo reports the JPG's file size.....NONE where changed from what the Camera device saved the file in.

The "File Properties" is what a printing device is going to read for output. Like the old saying "Garbage In, Garbage Out", one needs to tell the device How to print it, therein is the Document Size portion of the file's Property tag.
If I tell any editor to Save this file in xxxx and next time I open it, it reads cccc - that is a problem.

And once again - I can open All these images in All my editors and All will read the Same "Properties" for each photo/image/render/gif/png/Tiff....and so forth and so on.



Now, any Changing of these values will effect the Quality of the print. As none of these are set for printing to 8x6 or 9x10 or 11x8.5 or even some large Poster Size, the Pixels will be changed: squished (removed) or stretched (spread out and added). That technically is where the "Resample" comes in, the editor will attempt to give you a smooth pixel shift by "sampling" neighbor pixels to re-draw the resized image.
This is why in the issue of my OP I was attempting to make Poser render me the image EXACTLY the size and dimension and resolution I wanted so there would be No Resizing before sending to the final print process and therefor print out the render in all of Poser's glorious quality.

However, your pointing out the Resample function, for my case, as been the solution. The question still remains why Poser wants to Change my "Document" size that Input in Properties and makes me have to go into an Image Editor and Change it back to what I programed Poser to do Before I send to the Printer.