Some powerful free photo editing softwares.

Gimp
Photoshop alternative with lot of features.


Photofiltre
Editor: resize, rotate, flip, crop, text, transparency mask.
Editing tool: magic wand tool, color picker, paint, clone, smudge, blur, spray, line.
Color: brightness/contrast, hue/saturation, color balance, auto correct, add shadow, highlights, replace color, swap RGB channel,  gradient.
Filter: soften, sharpen, noise, relief, color, artistic, visual effect, deform (lake reflection), stylize, aged effect, frame (3D),  flatten, edges (color edge), textures, photomasque.


Photoscape
Editor: resizing, brightness and color adjustment, white balance, backlight correction, frames, balloons, mosaic mode, adding text, objects, drawing pictures, cropping, red eye removal, blooming, filters(e.g. Film effect, vignetting, cellophane, make a box, reflection, emboss, region out of focus, graduated tint, jitter, noise, blur, distort, crystallize.)
-Page allow you to merge multiple photos on the page frame to create one final photo
-combine multiple photos.
-easily create animated GIF
-Slice a photo into several pieces using splitter.
-batch edit, screen capture, color picker, raw converter.


Photopos pro
Edit - flip, rotate, resize, red eye, sharpen, blur, edges, filters, morphing filters, custom filter, add object.
Tool box-select, magic wand, crop, color picker, paint, custom paint, clone, super magic, lines,shape, fill, text, text over path, refiner. eraser, custom eraser.
Frame-classic, mask, overlay -
Effects:-
-deformation (perspective, shear, spin, pinch, wave, zigzaag, line slice, offset, random, circle, fish eye, stretch out)
-color (solarize, colorize, xolarize, posterize, fade to gray, metalize, RGB, duotone, grayscale, sepia), color curve. replace.
-light (shadow, inner shadow, glow, inner glow, high light, neon light)
Optics (mosiac, sphere, len 1 & 2, mirrors)
-magical (sparkles, on fire, stars, star dust, fireworks, bubbles, spheres)
-noise (gaussian , negative exp, rayleigh, uniform )
-more (button, bevel, 3D, outline, inline, emboss, paint, circular coordinates.)
-Layer.


Pixia
-Japanese painting and retouching freeware.
Paint - Fill, Tone Filter-artistic filter, Fip, Rotate, Text.
Image - Color adjustment, color balance, contrast,
Selection -mask,layer , blur effect.

Other popular and easy to use freeware you may like:

Paint.net
Picasa