Picnik closed on April 19, 2013, and is no longer available for use as of that date. However, the Picnik developers recommend using Google+ Photos Editor, a similar browser-based editing program. You can use Photos Editor by uploading a photo to Google+ and selecting the Lightbox View for editing.
After choosing the Lightbox View option, you can perform basic edits using the icons available. These icons allow the user to rotate, zoom in, crop or delete the photo.
For advanced editing, choose Edit from the Lightbox View menu. From here, you can Tune Image to adjust the brightness, contrast and color depth settings, or you can apply preset filters. Another option is Selective, which lets the user choose an object as the focal point within the image and apply saturation or other effects only to that part of the photo. The Details option lets you enhance sharpness manually or from a preset menu, and the Crop option allows the user to perform a freeform crop or apply an aspect ratio to the photo.
Additional filters and tools that are available on Google+ Photos Editor include Vintage, Drama, Black & White, and HDR Scape. Others include Retrolux, Center Focus, Tilt-Shift and Frames for a variety of customization effects, all available within the Lightbox View's Edit menu.