This picture was taken by the person submitting this report with a Canon S2IS digital camera. The camera recorded the date as 4/19/07 and the time as 2:03pm. The date is correct, and the time is at least approximately correct. The location is county road 308 in Blanco County, Texas. The approximate direction of the road is North.The photographer used the viewfinder to compose a scenic picture consisting of the dirt road, the bluebonnets, the tree & the clouds above the road. She was unaware of the image above the tree on the extreme right.Our pictures were downloaded from the camera to our computer shortly after our return home. A few days later, we were viewing the pictures on our computer monitor for the purpose of culling and editing them. Only then did we notice the image above the tree in the picture. When we zoomed in, we realized that it had a very defined shape, with clear, sharp edges.Our first thought was that this could be glare or reflection on the camera lens. Closer examination showed that there were clouds between the camera and the image, which seems to disprove that idea. I refer to image instead of object because the sheer size seems to rule out anything capable of flying.The only other explanation we could think of was that this could be the shadow of a conventional aircraft between the sun and the top of the clouds, but the clouds in that area of the sky are not solid enough to allow such a smooth & well-defined shadow. Also, a shadow should be black; and an aircraft would have to be huge for a shadow that size.Although I have made references to the enormous size of the image, we have no way to make any kind of estimate. The angle between the camera and the image indicates considerable horizontal distance, and its location above the clouds indicates considerable vertical distance; yet the image is very prominent in the picture. We have nothing which would indicate speed or direction of travel, if any. It was a very bright day, so automatic exposure time would be nil.There is a white or light-colored streak running diagonally across the image and extending down into the area behind the treetop. It looks very much like a thin tornado. We originally could only imagine a nose-down delta wing aircraft shape. After much review, there seems to be no reason to assume that the dark object extends down behind the white streak, which allows the concept of a different shape. The streak does not appear to be a cloud.We made 85 pictures in that general area (Texas Hill Country) on that day, but none of the others include that image. Had we known it was there, we would have dozens of pictures!The attachments are as follows: (1) Exact copy of original;(2) Cropped portion of original;(3) Cropped portion with gamma adjustment to enhance detail.We make no claims as to the nature of the image; only that these pictures are not posed and are not doctored in any way except as noted above. We are interested in finding a reasonable explanation. These pictures were shown to a camera shop owner in Tyler, who did not believe the image could be a problem with the camera. They were also shown to the KLTV weatherman in Tyler, who did not think it was a weather phenomena. Neither could offer a suggestion as to the nature of the image.