Output image file quality / JPEG artifacts
Standard Test Scene
The G6 provides five different output image size options, three different JPEG compression settings and RAW capture mode (which is essentially a record of data straight from the CCD without processing, the 'digital negative').
Below you will find crops of the same 240 x 180 portion of the center of a sequence of images taken at some of the available combinations of image size and quality. Crops shown are at 100%, saved as extremely high quality JPEG. The RAW file was converted to a TIFF using Canon Utilities RAW Image Task 1.2 (from ZoomBrowser EX).
Both the JPEG Super-Fine and Fine modes deliver images with virtually no visible artifacts, dropping down to the JPEG Normal compression level we can see some smoothing of flat areas and artifacts around detail. The G6's downsampling interpolation appears to be very good with clean images and no noticeable jaggies.
Canon Powershot G6 Digital Camera [7MP, 4x Optical]
Canon PowerShot G7 Digital Camera - Black (10.0MP, 6x Optical Zoom) 2.5" LCD