Revision Date: 19 November 2021

Overview/Features 4 is the best free image and photo editing application for Windows based PCs since 3.5. The application has been extensively rebuilt to improve functionality and ease of use while packing numerous new features into the now familiar user interface (UI). 4 works exclusively on the Windows operating system, requiring Windows 7 SP1 as a minimum. User Interface
User Interface (UI)

Some key features of 4:

The same intuitive user interface

Every feature and user interface element in has been redesigned to be intuitive and easily learned without assistance. 4 has improved the discoverability of new features while building on the now familiar User Interface (UI) of 3.5x.  Users of previous versions of will recognize the familiar interface, as should users of MS Paint and Adobe Photoshop.

Open & edit multiple images is able to simultaneously open multiple images and uses a tabbed document interface much like a modern web browser.  Instead of a piece of descriptive text, the tabs display a live thumbnail of the open image.

Image tabs make navigation very simple and fast, using only a single click to navigate to a new image.  New to is that the image tabs can be reordered with drag-and-drop.

Each open image shows up as its own Windows taskbar item (this can be disabled in the brand new Settings dialog).


Layers allow an image to be composed from a stack of images that are blended together. supports many layer blend modes, layer transparency and reordering of layers with drag-and-drop.

Unlimited History

Every editing action performed on an image is recorded in the History window.  The History list makes undoing actions as simple as clicking on a previous entry in the list.

The number of actions stored in an editing session is limited only by available disk space and memory.

Support for many popular file formats

Format Extension(s) Note*.pdn
JPEG*.jpg, *.jpeg, *.jpe, *.jfif, *.exif
JPEG XR*.jxr, *.wdp, *.wmpWindows 8.1+ is required
Bitmap*.bmp, *.dib, *.rle
Direct Draw Surface*.dds
TIFF*.tif, *.tiff
HEIC*.heicWindows 10 v1809+ required plus Microsoft’s HEVC Codec.
WebP*.webpMaximum image dimensions 16383 x 16383 pixels (format limitation unrelated to
AV1 *.avif

The native image type (*.PDN) preserves the layer structure of a composite image and is lossless, meaning no data is lost when saving in this format.  It is the default format for saving multi-layered images. If the image is a single layer, the format for saving defaults to *.PNG.

Webp and DDS file support is via bundled plugins by forum member null54.  Both plugins continue to be developed in parallel with

Many third-party tools (FileType plugins) exist which add new file types to  These plugins are available for free download from the forum

Performance optimized for today's hardware is optimized for the latest in multi-core processor technology, sporting a brand new, asynchronous, fully multithreaded rendering engine.

This new engine allows performance to scale with respect to the number of CPU cores whether you have 2, 4, 6, or even 16 of them. will run on both 32-bit and 64-bit version of Windows.

Automatic updates

Updates are free, and contain new features, performance improvements, and bug fixes.  Upgrading to the latest version is very simple, requiring only a few clicks of the mouse.

Extensive language support ships with 29 languages.

Available languages are: Belarusian, Chinese (Simplified), Chinese (Traditional), Czech, Danish, Dutch, English, Finnish, French, German, Greek, Hebrew, Hindi, Hungarian, Italian, Japanese, Korean, Lithuanian, Norwegian, Persian, Polish, Portuguese (Brazilian), Portuguese (Portugal), Russian, Slovak, Spanish, Swedish, Turkish & Ukrainian

Many third-party language packs are available. If your language is not presently supported check the forum for a free downloadable language pack.

Extensibility supports third-party developed plugins which add new effects, adjustments, and file format support.

Active community

The forum is a friendly, passionate, and ever-expanding online community of users.  The forum is family friendly. There you will find user discussions, help, tutorials, galleries and resources (like plugins and palettes) to download.

Access the forum from within by clicking the Help icon in the Tool Bar and selecting Forum from the menu.