If you are a Linux user looking for free video authoring tools, you have several tools at your disposal that are as good as commercial ones.

1) GIMP
GIMP is a versatile graphics manipulation package. It can be considered as an open source alternative to Adobe Photoshop.GIMP is ideal for advanced photo retouching techniques. Get rid of unneeded details using the clone tool, or touch up minor details easily with the new healing tool. With the perspective clone tool, it's not difficult to clone objects with perspective in mind just as easily as with the orthogonal clone.

2) Inkscape
Inkscape is an Open Source vector graphics editor, with capabilities similar to Illustrator, CorelDraw, or Xara X, using the W3C standard Scalable Vector Graphics (SVG) file format.
Inkscape supports many advanced SVG features (markers, clones, alpha blending, etc.) and great care is taken in designing a streamlined interface. It is very easy to edit nodes, perform complex path perations, trace bitmaps and much more. We also aim to maintain a thriving user and developer community by using open, community-oriented development.

3) CinePaint
CinePaint is used to retouch feature films and in pro photography.CinePaint opens high fidelity image file formats such as DPX, 16-bit TIFF, and OpenEXR, and conventional formats like JPEG and PNG. It has a flipbook for movie playback of image sequences in RAM. It supports 8-bit, 16-bit and 32-bit color channels, HDR and CMS. CinePaint is used for motion picture frame-by-frame retouching, dirt removal, wire rig removal, render repair, background plates, and painting 3D model textures. It's been used on many feature films, including The Last Samurai where it was used to add flying arrows. For still photography, CinePaint can import bracketed HDR exposures. It has gallery-quality 16-bit per channel color printing with GutenPrint. CinePaint's high dynamic range is crucial with B&W still photography, where images only have a single channel.

4) ImageMagick
ImageMagick® is a software suite to create, edit, and compose bitmap images. It can read, convert and write images in a variety of formats (over 100) including DPX, EXR, GIF, JPEG, JPEG-2000, PDF, PhotoCD, PNG, Postscript, SVG, and TIFF. Use ImageMagick to translate, flip, mirror, rotate, scale, shear and transform images, adjust image colors, apply various special effects, or draw text, lines, polygons, ellipses and Bézier curves.

5) Skencil
Skencil is a Free Software interactive vector drawing appliction. It is a flexible and powerful tool for illustrations, diagrams and other purposes.
A somewhat unique (for a drawing program) feature of Skencil is that it is implemented almost completely in a very high-level, interpreted language, Python. Python is powerful, object-oriented and yet easy to use.

6) F-Spot
F-Spot is a full-featured personal photo management application for the GNOME Desktop. Editing photos in F-Spot is a breeze. Easily rotate, crop, resize, and adjust red eye and other color settings with a few simple clicks.F-Spot allows for quick and precise color adjustments, including brightness, contrast, hue, saturation, and temperature.


7) Scribus
Scribus is an open-source program that brings award-winning professional page layout to Linux/Unix, MacOS X, OS/2 and Windows desktops with a combination of "press-ready" output and new approaches
to page layout. Underneath the modern and user friendly interface, Scribus supports professional publishing features, such as CMYK color, separations, ICC color management and versatile PDF creation.