Kouhei, I know that you are using GIMP so follow my tutorial.
You only need is GAP (GIMP Animation Package).
Here is the link:
http://sourceforge.net/project/showfiles.php?group_id=121075 [the
.zip one]
And for easy video to image transfer, use AviSplit (Search for it in Download.com). It will made indexing of videos fast. Just get the clip you want and you are good to go.
1. Open GIMP.
Xtns>Split Videos into Frames>Extract Video Range
2. Another window will open. Open the video file you want to convert. Input all other settings. Change
audiotrack to 0 (zero). Choose mode if you want single multilayer image or single image only.
3. Click
Video Range. On the right side, choose the frames you want. Check Loop and Play selection only. Play the selection. If it's ok, click OK.
4. If you don't check the
Create only one multi-layer image, you will only have one layer. In the tab above, choose
Video>Frames to image.
If you check the checkbox, you don't have to use this.
5. To make your gif at normal speed, delete every other frame (if you don't, the gif will become slow).
6. Scale your image to the desired size.
Image>Scale Image.
7. Optimize for gif.
Filters>Animation>Optimize (for Gif)
8. On the new window: Change mode,
Image>Mode>Indexed
Set
max colors to 256 and
color dithering to positioned.
9a. If you want to have a gif only image, Save as...
.gif
9b. If you want an image with gif, open another window. Create your image and save. Now on the gif window, change your canvas size to the size of your image.
Image>Canvas size.
Open as layers>Your image.
Put your image at the very bottom. Put border at your gif. Be sure it's on the last layer. Merge down the 2nd to the last image. View your animation.
Filters>Animation>Playback. Then Save as
.Gif.
I hope you understand my tutorial.
Happy Gimping.
*If you have questions just PM me.