• Step 1 - What is 'Tickling'?
Have a look at the two sets of images on the left. The image nearest to this text has been 'tickled', but the furthest one hasn't.

On a white background, you can see no difference, but on a darker background, such as blue, you can see little white spots at the edge of the second image.

The problem can be caused by any graphics package, and all that it basically is, is a curved shape, drawn onto a transparent background. When the image program takes away the transparent section of the image, and makes it white (default transparnet colour), tiny pixels of colour which are not quite white (added to smooth out the edge of the curve) remain.

Tickling is the process by which you remove these little blocks of colour, and a 'tickled' image has had the process done to it.

• Step 2 - Finding those little white bits
First, open up your image in Paint. Select a colour which is a shade unlike anything in the image, I choose a dark tan colour, and filled in the transparent part with that colour (the main white section).

The result you can see on the left. The whole of the transparent areas is filled with that yucky colour, apart from a few white dots.

• Step 3 - Getting rid of those little white bits
To do this step, it will help to enlarge the image slightly.

First, select the colour you filled in the backing with and then click on the 'Pencil' tool. Now click on, individually, all of the white dots, so that they disappear and merge into the background (you can see that I missed one).

Now fill all of that area in with white and re-save the image. To check that you still have transparency set, get to Image > Attributes (Ctrl +E).