Nikon Quality Test #2 to compare resized image quality from different resolutions & compressions

The purpose of this test was to answer the question whether a lower resolution or higher compression level to save storage space yields better quality of resized images for viewing on the internet. With these photos we can compare resized image quality for different resolutions and compression levels.

We selected Photo 3 as the target to resize to, take in VGA high mode 640 x 480 kb. Photos 4-10 were then resized to 640 x 480 using Paint Shop Pro 7.04 "Smart size" and then saved with 4 percent compression level. This 4 percent compression was chosen so that the resized images would be approximately the size of Photo 3 (132 kb) and so that the level of JPEG compression artifacts induced by resizing would be approximately the same in each resized images 4-10 . No other editing or unsharp mask was used either before or after any photo was resized.

I will be reporting my conclusion here later after I carefully review these test results.

Camera: Nikon Coolpix 950 in Program Mode was positioned 30 feet from sign on tripod. One photo was taken at each quality setting before resizing. Only Photos 4-10 were resized

Photo 10 was compressed with LZW (lossless) before resizing.

and an excellent site discussing "Compress or Resize"

http://geigy.2y.net/Tutorials/ResampleOrCompress/Default.htm

File loading, please wait.......

	Resolution		Image	Size (bytes)		# of Colors
	Original	Resized	Image	Original	Resized	Original	Resized
1	640 x 480	u/c	1-vga-basic-DSCN4212.JPG	39,646	u/c	52,208	u/c
2	640 x 480	u/c	2-vga-normal-DSCN4211.JPG	62,728	u/c	52,599	u/c
3	640 x 480	u/c	3-vga-fine-DSCN4210.JPG	131,949	u/c	52,567	u/c
4	1024 x 768	640 x 480	4-xga-basic-DSCN4209b.JPG	92,276	119,834	86,041	48,244
5	1024 x 768	640 x 480	5-xga-normal-DSCN4208b.JPG	174,963	124,557	92,305	50,177
6	1024 x 768	640 x 480	6-xga-fine-DSCN4207b.JPG	357,940	123,580	97,868	51,798
7	1600 x 1200	640 x 480	7-basic-DSCN4206b.JPG	227,549	127,290	135,871	48,911
8	1600 x 1200	640 x 480	8-normal-DSCN4205b.JPG	407,194	127,890	141,324	49,207
9	1600 x 1200	640 x 480	9-fine-DSCN4204b.JPG	789,218	126,754	138,000	47,848
10*	1600 x 1200 raw	640 x 480	10-HI-DSCN4213b-LZW.TIF	2,806,802	125,540	132,366	46,436

* Photo 10 was compressed with LZW (lossless) from 5,767,241 to 2,806,802 bytes before resizing

u/c = unchanged

Following are screen shots of 7:1 magnified side-by-side comparisons

Click arrows below to see 6 photos