The Microsoft ICE Program automatically combines photos into composite photos.
The user simply drags 2 or more photos into ICE and it "flattens" the photos mathematically and then automatically adjusts brightness and contrast based upon the f-stop and shutter speed.
ICE then blends the pictures together to form a nearly perfect photo and will automatically crops the photo before saving
ICE will work with groups of photos arranged horizontally or vertically
It will also take an array of photos (e.g., 2 tall x 3 wide) and combine them as well.
No additional user input is required.
The user can specify if subsequent pictures in the set were from a camera position change from rotating or translating (i.e., move sideways to obtain additional shots). ICE trys to do this automatically by user can override.
ICE does an excellent job removing parallax effects from the photos and usually produces a perfectly finished photo.
If the composite is a very wide angle shot at near infinity focal length, then scallopping on the edges results from lense distortion. ICE automatically trims this off when the merge is complete.
Once the photo composite process is complete the total field can be drastically reduced. Here the left side has extraneous content.
This allows extraneous perimeter content to be removed easily after the compisting is done.
The final composite picture, with automatic cropping and output is all done by Microsoft ICE. That result can then be taken into your favorite photo editor for further processing.
I use Corel Paint Shop Pro (PSP) for all of my photo editing. It has intelligent digital noise reduction, brightness and contrast, and hue and saturation adjustments.
But you also have the option to manually tweak the recommended corrections or specify them manually to suit your tastes or requirements.
In this photo I used advanced but manual selection tools to extract a head from one photo and insert it into another photograph.
I was then able to use the PSP color_changer tool to match the manikin skin tone to that of the transfered face skin tone.
Another PSP widget is the straighten command. It allows you to sketch a virtual line on the photo and PSP will automatically rotate that line to the horizontal and automatically recrop the photo.
This is a great tool for removing that annoying 2-3 deg slant that sometimes sneaks in from poor camera position or angle.
Often a photo has a subtly weird perspective and a simple straighten command is all that is needed to clean it up.
This photo is 10x better with just a very small rotation to help recompose the picture
PSP also has a perspective_correction tool that can help "square" up photos with lots of depth of field distortion
This plaque was way up on the side of a building but the perspective correction helped make it look as though it were shot at eye level.
This photo retouch uses mulotiple photo editing commands. First I started with a little perspection correction.
Then some rotation adjustment helped to create an entirely new photo from a near disaster. A little tweak of brightness/contrast and hue/saturation turns this photo into a very nice take.
This photo has the problem of reality - someone has setup a construction tower right in the middle of the skyline in a this midieval town.
The PSP clone_brush allows you to paint over sections of a photo with content from elsewhere on the photo. This cloning process makes it easy to replace one area of the photo with a content from another area simply using a paintbrush action. Take a double or triple take on this one - you can not see any artifacts from the crane removal.
I used the clone and rotate commands here. First the clone brush to remove the grafitti. I "simply" pick a section of nearby clean wall and use that as the source for a clone paint job over the grafitti.
And then the straighten command to get the composure right.
The clone brush has two basic adjustments; hardness and density. The density is like the coverage from a spray paint can. Lower density only "paints" over some percentage of the target area. This allows you to "touch up" an area with out completely replacing the original content with the cloned information. 
The hardness controls the density of fill as you approach the outside edge of the circular or square "brush". 100% hardness give the brush sharp edges while lower densities effectively result in a feathering effect around the edges. Finally a little straighten and this picture looks great.
You can use the clone brush to an extreme if you are patient enough and have lots of reference areas to pull content from on the photo. This photo had a number of problems - unwanted foreground bystanders, and a few people hanging out between the pillars at the far end of the courtyard.
There are a few artifacts from the cleanup but most of them would not jump out if you didn't know the photo had been edited.
This is a great example of what you can do with the clone brush. This was a great shot but all the construction tape pretty much ruined it.
20 minutes later the tape is gone without hardly a trace to the unkowing eye. A lot of work but less than the time to take down all the tape and put it back up onsite.
Here I had a great group shot but the background was poorly composed, poorly cropped, and rotated slightly.
I found another picture that was shot from nearly the same location and used ICE to combine the two pictures
But in this case the pictures didn't line up nicely so there were several perimeter areas that just didn't have content. Here I used some manual selection tools with copy and paste commands to copy large chunks of material from elsewhere (i.e., same photo or another photo).
Then I went to work with the clone brush to fill in remaining gaps and to blend in the transitions to the newly pasted areas. Finally a straighten command to get the picture composed properly and the result is another great saved picture.
PSP has another great utility call photo blend. It allows you to take two very similar pictures and semi-manually blend them together, omitting things in one photo and using parts of the other photo to replace them. This camera location had a lamp post and wires in the middle of the field of view that couldn't be shot around.
I had a second photo shot from very nearly the same position but different enough that I was able to see what was behind the lamp post. By using the blend function I was able to remove the lamp post from the master picture and blend in the background that was exposed in the second photo.
For my first attempt at blending photos I was very impressed. This would have taken hours using cut and paste and the clone brush and it wouldn't have turned out nearly as good. I then used the clone brush to "remove" the power line with nearby pixels resulting in a nearly perfect correction.
