The list of uncompressed PPM images with sizes is here.

If you wish to download the LPCB test images, here's what you should do.

Click SEARCH METHODS on the bottom of page http://photojournal.jpl.nasa.gov
Find Search by Feature Name, enter a and press Enter.
Download all images with
(1) date between 2011-01-01 and 2011-03-31,
(2) width less than 10500 and height less than 10500,
(3) three channels, e.g. 3456x2304x3, skip all images with resolution ending with x1.
Conversion from TIF to PPM by NConvert:
nconvert.exe -out ppm *.tif
Exclude ex-JPEGs using this Detector for ex-JPEGs.
Most probably you have downloaded 110 images, and 51 of them have been detected as ex-JPEGs.
The remaining 59 images were split into two sets:
21 images (836 Mb) with stars, galaxies, and nebulae,
38 images (493 Mb) with everything else: Earth's surface, space bodies, laboratory shots, etc.

Search for "sample raw images" on photographyblog.com, only pages with dates between 2011-1-1 and 2011-4-4.
With the advanced Google search you will most probably see links to the following 7 pages:
18 Jan 2011 http://www.photographyblog.com/reviews/sony_a580_review/sample_images/
26 Jan 2011 http://www.photographyblog.com/reviews/olympus_epl2_review/sample_images/
 7 Feb 2011 http://www.photographyblog.com/reviews/olympus_xz1_review/sample_images/
17 Feb 2011 http://www.photographyblog.com/reviews/sony_a55_review/sample_images/
17 Mar 2011 http://www.photographyblog.com/reviews/fujifilm_finepix_x100_review/sample_images/
22 Mar 2011 http://www.photographyblog.com/reviews/canon_eos_600d_review/sample_images/
24 Mar 2011 http://www.photographyblog.com/reviews/canon_eos_1100d_review/sample_images/

As of April 2011, neither IrfanView nor XnView nor NConvert can correctly handle raw images from Fujifilm FinePix X100.
The same with Canon EOS 1100D, so Canon EOS 600D was chosen.
Plus images from the most recent Olympus and Sony reviews with sample raw images.
On the Sony A55 page images 12, 13, 14 were excluded as they are very similar to image 11, and
on the Canon EOS 600D page images 8, 9, 10, 11 were excluded for the same reason.
Conversion to PPM format was done by NConvert:
nconvert.exe -high_res -raw_camerabalance -out ppm *.orf *.arw *.cr2
None of the 50 images were detected as ex-JPEGs.
Olympus' images are 10 megapixels each (30 Mb), Sony's 16 and Canon's are 18.
All three cameras got Image Quality 4.5 on the Review Conclusion pages.

The set with Fujifilm FinePix X100 images may be added later.
One 24-bit image from a Nikon camera is used here (search for nikon24).
Return to the main LPCB page.