Bruce Murray Space Image Library
Beagle 2 lander on Mars?
Here are three grayscale views, beginning with the same one as above, ESP_037145_1915:
Here is another view from a different HiRISE image, ESP_030908_1915.
And one more, ESP_039308_1915:
Here is a flicker gif comparing the three.
Here is a detail on the lander.