Sometimes I need to do a little graphics work, but I do not have Photoshop.  Instead I use a great free tool called Paint.NET.  It is an open source image editing project built with C#.  It has a very rich feature set in many ways similar to Photoshop.  Community plugins are also available.

Like other graphics tools, sometimes you have to figure out the tricks to get things done.  In this case I will be showing one way to seamlessly blend the edges of two photos.  I needed to do this for some scrolling banner images, but there are many other uses for this technique.

First you want to open both images.  Then expand the canvas on the first image in order to fit the second image.  This is done by selecting the “Image” menu item, and then the “Canvas Size” sub item.

Now copy the second image and paste it onto the second image into a new layer.  You can use the “Paste in to New Layer” option under the “Edit” menu.  Move the edge of the second image over the top of the first image.  You will need a good amount of overlap to blend with.  (The “Move Selection” mode is activated by clicking on second item at the top in the bottom right “Tools” bar.)

Now select the gradient tool.  Set the gradient mode to “Transparency Mode”.  Set the Secondary transparency to 0.  Set the Primary transparency to 78 (Note: you may have to experiment with different levels of transparency).

Apply the gradient by clicking and dragging to the right (Note: make sure “Layer 2” is selected.  We are applying the gradient to this layer only).  You may need to redo this a few times to get the proper distance.  Notice that the first image is now bleeding into the second.

There is still one problem left.  Even though the images are somewhat merged there is a distinct line separating them.

One way to deal with this is to apply a blur.  There are many different ways to do this.  Sometimes a “Radial Blur” is best, and other times a “Motion Blur” works better.  It may be necessary to apply multiple blurs.  In this case a radial blur will be applied and then a motion blur (Note: the blurs are only being applied to the semitransparent edge of “Layer 2”).  First select the area to blur.

Blur options are available under the “Effects” menu and then under the “Blur” sub menu.  First apply a radial blur.  Just experiment with the settings until you find something that looks good.  I used the settings below.

After applying the radial blur you will notice that only a slight line is remaining.

Select an area for a motion blur.

Apply a small motion blur.

And finally we have merged and blended image edges.  The image transition is almost seamless.

I hopes this helps someone else trying to do this.  There are probably many other ways to do it.  This is just the approach that I took.