Create a new, rather large document. I made mine 800x600 pixels. If you plan on printing your card, make the X and Y resolutions at 300dpi. Give it a white background.
On the background layer, we'll apply a gradient. Make your foreground color either a dark red or a dark green and make your background color black. Apply a radial gradient to the background.
Create a new layer and name it "tree reference." Get out the pencil tool. Choose the Circle (01) brush and make the color white. Drag a ruler to the center of the image. With the pencil tool, click once where you want the top of the tree to be, using the ruler as a reference. Now, hold Shift and you should see a line follow the mouse pointer from the point at the top of the tree. Click where you want the base of one side of the tree to be. Do the same for the other side. This will be our reference for our Christmas tree.
Now we need an image of our Santa Claus. Go find one somewhere on the net, or you can use this one. Place him in the center of the tree. You can use the ruler to be sure he is center. Create a new layer and name it "tree." Get out the Paths Tool. Starting at the top of the tree, create a diagonal path down towards Santa's star.
Still using the paths tool, go to the paths dialog and switch from design to edit. Click a path and manuever the little squares to curve the lines, like I have below.
Download these brushes. Because they are a .tar.gz file, you will need a program such as 7zip to extract them unless you are running a Linux platform. Copy them into your Gimp brushes folder.Click the brush tool (don't worry if your path disappeared, we'll make it come back up later) and in the brush dialog, click the little refresh button. Your brushes should appear.
Select the star brush I have selected above. In the other brush dialog, apply these settings:
Go ahead and change the brush's size to 0.10 pixels instead of what it is now. Click the Paths tab next to the Layers tab. Double click on the white space on the only path listed. Our path should show up on the document. Click the "Stoke Path" button. Select the "Stroke With a Paint Tool" option and select the paint brush. Enable brush dynamics and click ok. You should have something like this:
Before we go any further, we need to install a couple of filters. Download these filters from the Gimp plugin registry and install them. To do that, simply save the SCM file avaliable for download and paste it into the Scripts folder, in the same archive as the Brush folder. To activate the script, go up to Filters >Script-Fu > Refresh Scripts. A menu should pop up next to the Filters Menu named "Script-Fu".
Open your ecard back up. Select your tree layer. Go to Script-Fu > Layer Effects > Color Overlay. Select a hue similar to either the dark green or dark red you chose at the beginning of the tutorial. Choose the setting Overlay and keep the opacity at 100%. Click ok.
Now go to Script-Fu > Layer Effects > Outer Glow. Keep the default settings, except lower the opacity to 14% and change the blending mode to Screen. Click ok. (Note I have hidden the tree reference layer below.)
Now let's add a star at the top of the tree. Create a new layer and name it "star." Paint a white star at the top of the tree. Also paint a smaller star at the top of the star above Santa's head. Apply outer glows and color overlays like we did in the last step.
Now we'll add in some text. Type in "Christmas," or whatever word you would like. Place it behind the Santa layer. I used size 80 font Arial Bold. The color is the opposite color of my background. (IE red if your background is green, and vice versa). I made the star above Santa's head in the center of the text. Let's give the text some style.
Go to Script-Fu > Layer Effects > Inner Shadow. Keep everything default and make the size 4. Click ok. Go to Filters > Light and Shadow > Drop Shadow. Make the offsets 0, the blur radius 8, and don't allow resizing. Click ok.
Now go to Script-Fu > Layer Effects > Bevel and Emboss. Change the type to Inner Bevel and raise soften to 4. Click ok.
We aren't done with the text yet. Select the text layer again, and go to Script-Fu > Layer Effects> Color Overlay. If your text is red, use #ff0000. If your text is green, use #1fae1c. Set the blending mode to Overlay, and click ok. In the layers dialog, drag the color overlay layer that was just created to above the rest of the layers that make up the text. Lower the opacity to about 63%.
Let's add a reflection to the text. Hide all of the layers that do not make up the text. Edit > Copy Visible. Edit > Paste As > New Layer. You should now have the text all on one layer without any distortion. Go through and delete all of the separate pieces that made up the text to begin with, except for the one we just made. Your picture won't look any different- we just put all of the pieces that make up the text on one layer.
Now duplicated the text layer. Go to Layer > Transform > Flip Vertically. Place it underneath the original text, as if it were a reflection.Right click the reflected layer, and select Add Layer Mask.... Select the first option (full opacity) and click ok. Reset your colors to black and white. Apply the gradient from bottom to top, making a reflection.
Now add some "Merry" text and some more icons like in previous steps. For the "Merry" font, I downloaded this font. All I did with the text was give it a drop shadow like before and stroked the edges with light green. As far as the icons go, just search for Christmas or holiday icons on Google and you are bound to find some.
Now we'll add some snow. Create a new layer and go to Filters > Render > Clouds > Solid Noise. Raise the X and Y size to 5 and raise the detail to 5. Click ok. Go to Colors > Hue/Saturation. Take the Lightness all the way down and click ok. We still need some more dark spots, so get out the burn tool and burn it in a couple places.
Filters > Blur > Gaussian Blur. Blur by 30. Now go to Filters > Noise > Hurl. Use 10, 41, and 1. Click ok. Go to Colors > Threshold. Drag the arrow to about the third line. Click ok. Go to Filters > Blur > Motion Blur. Use linear type, length 3, and angle 212. Click ok. Set the layer mode to Overlay and lower the opacity to about 42%.
I forgot to add the reflections for the Santa, tree, ornament, and gift, so I went ahead and did that as well, the same way the text was done.
Wasn't that easy? Now you can use it as a wallpaper, or email it to your friends and family, even your co-workers, or boss. It's a nice and easy way to get every one into the holiday spirit! Merry Christmas everyone!