Image-stacking and mosaic-making software utility

IMerge is a program which allows multiple images to be placed onto a large virtual 'canvas', and arranged to produce a single large composite image, or mosaic. In regions where multiple images overlap, the result is an average of all contributing images - this has the effect of improving the signal/noise ratio.

It is possible to 'feather' the edges of images to avoid visible boundaries, and it is also possible to adjust the brightness of each image in order to produce the best match with other images. Once a mosaic has been arranged, iMerge allows the overall brightness levels to be adjusted using a flexible histogram remapping tool.

The images can come from BMP or AVI files (colour or monochrome), or FIT files (monochrome only). Output can be saved in BMP or FIT format.

Examples of images generated with iMerge can be seen in my Gallery - the Crab nebula, M42, Flame and Horsehead, and large moon mosaics were all made with prototype versions of iMerge.


The downloadable ZIP file contains the program iMerge.exe, and a rich text file iMerge.rtf containing a description of its features and how to use them (you can read this file using WordPad.)


This software is offered 'as-is' with no guarantees made as to fitness or suitability for any purpose, and no liability assumed for any loss or damage resulting from its use. I have used it regularly and have not had any trouble with it. However the downloading and use of the program is done at your own risk.

You may not sell or re-distribute iMerge, but you may download it from this site or publish links to this page.


iMerge is downloadable for non-commercial use, as 'conscience-ware'. This is not the same as freeware or shareware.

When you have used iMerge for a while, I would ask you to consider what you think it is worth to you, and maybe think about making a small donation - say, the cost of a pint of beer - using PayPal (all major credit and debit cards accepted) by clicking on the 'Donate' button below - this will greatly encourage me in the futher development of iMerge and other programs. So far I have not been greatly encouraged :-(

iMerge contains a link to this page from the 'Help->About' menu option, should you wish to return here in the future..

Alternatively if you have comments, feedback or suggestions concerning iMerge you can email me.


iMerge est gratuit pour télécharger. Si vous le trouvez utile vous pouvez m'acheter une bière virtuelle en faisant une donation de quelques euros. Cliquez le bouton 'Donate' de Paypal!

Robert Mauran a produit une traduction française des instructions. Vous pouvez la télécharger ici.


Der Download von iMerge ist kostenlos. Nach dem Sie iMerge eine gewisse Zeit benutzt haben, sollten Sie sich überlegen, welchen Wert diese Software für Sie hat und eine kleine Spende in betracht ziehen. Sagen wir den Preis eines Bieres. Dazu klicken Sie bitte die PayPal 'Donate' Taste. Die Spende dieses virtuellen Bieres wird mich stark motivieren iMerge und andere Programme weiter zu entwickeln!

Download iMerge version 1.2 (36KB)...

Back to Astrophotography homepage