Saved image from FF, into Photoshop with larger dimensions

For a stand-alone texture filter from Filter Forge (that doesn't require an image), is it possible to do the following - WITHOUT LOSING THE HIGH-RES "LOOK"/QUALITY of the image saved from FF, once inside Photoshop:

(1) Save the FF texture as an image at say, 600x600 px
(2) Import/drop that image into a Photoshop file, say 3000x3000 px, at 300dpi/ppi (to take up the entire bounds of 3000x3000 px).

(I know I can do this all inside Photoshop with the Filter Forge plug-in, but my computer takes forever on bringing some FF textures into it, when Photoshop size is 3000x3000 px.

Similarly, if I save an image using the stand-alone of FF with a size of 3000x3000, it takes a long time, for some filters. But 600x600 is no problem).

Thanks for getting back to me. Yes, I wanted to render a particular texture to an image away from the Photoshop Plugin, directly from FF at a lower res. and then try importing to Photoshop, for a larger res. image - and see if that was faster, but still retained good quality. I've played around and found that I was able to get a good result by:
* Saving an image from FF at size 1000x1000, as a TIFF with No Compression (the "no compression") was the key to retaining the appearance quality
- (and I needed to keep to about 1000px, as higher would take too long)
* Dropping the TIFF into Photoshop - quality was great - 300dpi 3000x3000px

(I haven't had to do this with other textures, just the one - I need to learn how to make filters more efficient).