Best image resizing plugins? Pros and cons.

Image resizing is an important part of image processing work. There is a huge array of different methods with different benefits and sometimes abhorrent artifacts. I'm new to Photoshop but I'm impressed with the wide array of enlargement plugins available. A few enlargement plugins have been mentioned in these lists but I suspect that there's not a single solution that works best for every image.

I'd love to hear about your favorite resize option (preferably with the method it uses); how it works best for you and when the results leave something to be desired. I'm really after the best image quality rather than the cheapest or easiest to use.

This is my draft list from a little searching:

  • Photoshop built-in
  • Alien Skin Blow up (Vector based)
  • ON1 Resize (Fractal based)
  • PhotoZoom Pro (S-Spline based)

Thanks for your help in navigating this.
I'll try kicking this off myself.

  • Photoshop built-in (Image Size - Preserve Details) appears to be doing a bicubic resize followed by a smart sharpen
I haven't tested this comprehensively but it doesn't appear to preserve edge detail from the image.

  • PhotoZoom Pro can 'hallucinate' detail
Looking at the examples, something strange happens to the hair in the corner of the face example and the depth of field in the shell example creates an unexpected pattern on the rock it's sitting on.

I notice that PhotoZoom Pro has a whole host of options so it may be possible to compensate for this.
As I'm sure you must know, discussion of the best image resizing algorithm / software package has been a real can of worms that dates even from pre-Photoshop days, ie, the late 1980's through late 1990's, when many of the algorithms were still being discussed in Computer Science classes and graduate school research. For example, a Google search on {image scaling algorithms comparison} produced over 10 million, very reasonable hits. Personally, I don't have time to discuss that enormous literature base here.

I own and use all three of the image resizing packages you mentioned, plus a couple more. My opinion is that the only way to tell which is "the winner" is to try them for yourself on the particular image that you need resized. After following this field for at least 2 decades, I find general discussions without reference to specific example images to be next to useless (at least for the better algorithms). In fact, I find that often, one algorithm will be better in one part of the image, whereas another algorithm will be better in another part of the same image. Some do better in areas with a relatively small number of well separated, sharp, well defined edges, some do better in areas where there are many, closely (and possibly regularly) spaced edges, some better where there is a more natural, fractal-like texture that needs to be interpolated. IMHO, there is absolutely nothing that beats personal experience when working in this area.


Tom M

PS - BTW, I have never had a problem with PhotoZoom Pro inventing unbelievable texture or edge artifacts, but I always tweak every available knob in any software I am using, LOL.
Thanks Tom.

So would you recommend getting a bunch of different plugins and trying them on different images until you get a feel for which one will work best? Would it be too much to ask what your "couple more" plugins are?

Perhaps I was too limiting in asking for a favorite. Would it be possible to give a favorite for each algorithm type? I suspect that some plugins which using a similar algorithm are simply better than others. Are there any hybrid plugins which use content aware algorithm selection?

Is it possible to generalize things such as: fractal based plugins are best for natural textures?

When say that experience is the most important thing, do you mean experience with use of the plugins? It's really that experience that I'd like to tap into, having not used these plugins yet.

Maybe I should just ask:

1. Which enlargement plugins do you use?
2. Which enlargement plugins have you tried but don't use and why?

Ideally I'd ask which sort of images you think the plugins you use are best for but as you say, that gets a bit vague.
Personally I use Luminar (as a Photoshop plugin) for resizing photos. It's biggest advantage is that it has lot of other options and can be used as an independant photo processing tool. The disadvantage... Well, it's not cheap I'd say.

Has anybody used ON1 Resize? Interested in your impressions after it.