PixInsight is a powerful image processing package that I've been using lately for my astro images. There is a lot of tutorial and other helpful PixInsight material on the PixInsight site and elsewhere on the web, but it's sometimes hard to locate specific items.

This page of useful PixInsight links is organized by broad topic. I hope you find it useful.

PixInsight Official Website Material
PixInsight Resources - A new and comprehensive collection of PixInsight tutorials, examples, and documentation
PixInsight Software Tutorials - PixInsight tutorials authored by PTeam members and expert users.
PixInsight Processing Examples - PixInsight processing examples authored by PTeam members and expert users.
PixInsight Reference Documentation - Detailed PixInsight documentation for many PixInsight Processes

PixInsight Usage
PixInsight Videos - This Video Tutorial Site will direct you to many great videos from Harry Page, both Intro and Advanced
PixInsight Video Tutorials - Medium and Advanced Tutorials in German and English from Gerald Wechselberger
Screen Transfer Function and Preview Windows Tutorials - from Craig Stark at Stark Labs
A New User's Experience - PixInsight Workflow from Dogwood Ridge Observatory
Processing Examples - A Varied List of Processing Examples from PixInsight Guru Alejandro Tombolini
PixInsight Tutorials - A Detailed Set of PixInsight Tutorials from Kayron Mercieca

Complete Image Processing Tutorials
NGC 1808 LRGB Processing Example - Two comprehensive PixInsight Video Tutorials by Vicent Peris, including raw image data
Image Process Demo Sword of Orion - Video tutorial from Harry Page
M106 LRGB Processing Part 1 - Video tutorial from Harry Page
M106 LRGB Processing Part 2 - Video tutorial from Harry Page
M51 Image Process Demo - Video tutorial from Harry Page
DSLR Workflow - Wide Field Orion - A detailed DSLR tutorial from Kayron Mercieca at Light Vortex Astronomy.
HDR LRGB Workflow - The tutorial goes through an entire LRGB workflow including making a HDR composite starting from the raw calibrated monochrome images to the end result with absolutely everything in-between. There are 95 screenshots in total so everything is extensively documented.
IP4AP Tutorial Series - Warren Keller and RBA have teamed up for an extensive series of PI tutorials. Online and DVD.  Not free, but well worth it.
M42 PixInsight Tutorial - Tutorial from David Ault

Image Calibration and Integration
Master Calibration Frames: Acquisition and Processing - by Vicent Peris, PixInsight
DSLR Raw Workflow, Including Calibration - Another take on Vicent's calibration process, with DSLR Info
Image Integration Techniques - A downloadable presentation by Jordi Gallego
Image Alignment and Stacking - Video tutorial from Harry Page
New PixInsight Tutorial: Pre-processing (Calibrating & Stacking) your Images- Tutorial from Kayron Mercieca
This tutorial covers what one needs to do with monochrome images that have been pre-processed separately in order to be able to later colour-combine them and apply further post-processing.- Tutorial from Kayron Mercieca
Synthetic Flats with PixInsight- Tutorial from David Ault

DSLR Raw Workflow - A detailed list of notes and forum links for processing DSLR data
DSLR Workflow Tutorial - A detailed and complete workflow processing DSLR data from Kayron Mercieca

Image Processing and Enhancement
Balancing the Histogram - YouTube video from RBAF
Colour Calibration - Harry Page video tutorial
Color Calibration - YouTube video from Carlos Sonnenstein
Luminance Processing - by Rogelio Bernal Andreo
Multi-Scale Processing - by Regelio Bernal Andreo
HDR MultiScale - Harry Page video tutorial
Dynamic Range and Local Contrast - Advanced techniques tutorial from Vicent Peris
This tutorial covers the procedure for colour-calibrating RGB images to produce a realistic colour reproduction. - Tutorial from Kayron Mercieca

Deconvolution - Another of Juan's great little tutorials, on the PI Forum
M81-82 Deconvolution - M81 and 82 Deconvolution and Noise Reduction by Juan Conejero
Deconvolution Tutorial - A 10 minute video tutorial from Mike Wiles
Deconvolution Tutorial - A detailed tutorial from Manuel Jimenez
M27 Deconvolution Example - Good deconvolution example from Alejandro Tombolini

Noise and Gradient Reduction, Dynamic Background Extraction (DBE)
Noise Reduction with MultiScale Median Transform - by Juan Conejero, PixInsight
Background Noise Reduction - Scroll down through this forum posting for a very useful tutorial on ATWT from Juan Conejero
Noise Reduction in Astronomical Images using ACDNR - by Thomas W. Earle
ACDNR Noise Reduction - Video tutorial from Harry Page
A Comparison of Noise Reduction Algorithms - Tutorial by Juan Conejero, PixInsight
Removing Gradients - by Rogelio Bernal Andreo
Automatic Background Extraction - Craig Stark
DBE Magic - Harry Page video tutorial
Noise Reduction - A tutorial from Kayron Mercieca

LRGB, HDR, and Ha
LRGB Combination - A good forum discussion of how to properly combine LRGB frames
LRGB Combination - Harry Page video tutorial
HDR Composition - The new HDR tool, described by Juan
HDR Composition - Tutorial from Rogelio Bernal Andreo
HDR Composition - YouTube video from PixInsight
Adding Ha to a RGB Galaxy the Vicent Peris Way - Harry Page tutorial
Rosette Nebula - PixInsight Workflow for Narrowband Images (with H-α as Luminance) - Another detailed tutorial from Kayron Mercieca
PixInsight Guide for Combining Narrowband and RGB (H-α and O-III) - tutorial from Kayron Mercieca

Star Mask Production for Linear Images - Harry Page Video Tutorial
Star Mask Uses with HDR Wavelets - Harry Page Video Tutorial
Reduce Star Diameter with Star Mask - Tutorial Video from Gerald Wechselberger - click link on page for video
This tutorial covers a number of methods for the production of useful masks that aid in post-processing targeted features of an image. - Tutorial from Kayron Mercieca

Mosaic Construction with Star Alignment - YouTube video from PixInsight
Mosaic Construction - Useful forum thread, with a link to the Mosaic Video Tutorials on the PI Site
Mosaic Construction - Yet another helpful video from the famous Harry Page
Gradient Merge Mosaic Tool - PI Forum discussion of Georg's great new tool
Gradient Domain - Another PI forum discussion, led by Georg Viehoever, developer of the tool
2 Frame Mosaic of the M31 Region - Shorter YouTube video from PixInsight
Sky and Telescope July 2011 - Article on Mosaic Construction by RBA - you must be a subscriber to access
Rho Ophiuchus Mosaic - Mosaic discussion in the Ice in Space forum
PixInsight Mosaics - Detailed Mosaic Tutorial from David Ault

Processed Images
flikr PixInsight Group - Over 400 processed PI Images

Miscellaneous Useful PI Tools
Dynamic Profile Module - YouTube video demonstration by its author, Sander Pool
Dynamic PSF - The new Point Spread Function, described by Juan
Redesigned PixelMath Tool - by Juan Conejero, PixInsight
Advanced PixelMath Tutorials - Tutorial Videos from Gerald Wechselberger - click links on page for videos
Moving Data from CCDStack to PixInsight - A Cloudy Nights discussion
PixInsight Star Removal - A Tutorial by David Ault
PixInsight Star Halo Removal - A Tutorial by David Ault
Reduciung Star Sizes - tutorial from Kayron Mercieca

General Reference Material
The Officially Unofficial Reference Guide from Rogelio Bernal Andreo
PixInsight LE Documentation - Although PixInsight LE is obsolete, there is still a lot of useful information in these online Help files
New Project Functionality in PixInsight 1.7 - YouTube video from PixInsight
Harry's PixInsight Video Tutorials - A comprehensive series of PixInsight Tutorials from Harry Page