What it does
On the left sits the folder tree (Pictures, Desktop, the drives), on the right the thumbnail grid of the open folder. The thumbnail size switches in the toolbar or with Ctrl+wheel in five steps from 80 to 320 px. A double click or Enter opens the picture across the window, the arrow keys or the mouse wheel page to the next and the previous one, F11 stretches it over the whole monitor and S starts a slideshow.
In the single-picture view the photo is fitted to the window and stays sharp, Ctrl+wheel zooms around the pointer and dragging pans. Holding the left button shows a 1:1 loupe under the pointer. L and R turn the view; the file is left alone. The Info panel (I) shows the dimensions, camera, lens, exposure, focal length, GPS and an RGB histogram.
A folder can be sorted by name, by the date taken from EXIF, by file date or by size, and filtered with the Filter box, where * and ? work as in Explorer. Several pictures are selected with Ctrl and Shift, Explorer style. The only file operation is Del, which moves a picture to the Recycle Bin after asking.
Status: version 1.0.0
First public release
Folder tree, thumbnails in five sizes, a viewer with a loupe, full screen and a slideshow, sorting and a filter, an Info panel with EXIF and a histogram, multi-selection, dark and light theme following Windows. It opens a folder or a picture from the command line, through "Open with" and by dropping it onto the window.
It only views
MHView never writes to a picture: rotation, zoom and sorting change only what is on screen. There is no editing, no conversion and no batch renaming, and in the first version that is by design. Sorting pictures into folders and moving them comes in a later version.
Formats and HEIC
It reads .jpg .jpeg .jpe .jfif .png .gif .bmp .tif .tiff .webp .ico and .heic .heif .hif. GIF and TIFF show their first frame; WebP only when Windows has the codec installed (Web Media Extensions).
iPhone photos in HEIC open even on a PC without the HEVC extension from the Microsoft Store: the Windows codec is tried first and, when it is missing, the bundled libheif library takes over. That is why the .exe is 1.3 MB instead of the usual few hundred kB. EXIF is read by the program's own reader straight from JPEG and HEIC, so the date taken, the camera and the GPS do not depend on the codec.
Why it is fast
JPEG is decoded straight at a reduced size, so a thumbnail of a 24-megapixel photo takes tens of milliseconds instead of hundreds. Several threads build the thumbnails, what is on screen first, and the grid repaints only the finished cells. While paging, the previous and the next picture are decoded ahead, so the arrow key shows them at once. The EXIF orientation is applied on load; phone pictures come up the right way.
Thumbnails are kept in memory for the open folder only; no cache is written to disk. The settings (last folder, thumbnail size, window position, theme) live in MHView.ini next to the program, or in %APPDATA%\MHSW.NET when that folder is not writable.
Keys
| Key | What it does |
|---|---|
| Enter, double click | Opens the picture across the window; in the viewer, back to the thumbnails. |
| Arrows, PgUp, PgDn, Home, End | Move around the thumbnails; in the viewer, the next and the previous picture (the mouse wheel too). |
| F, F11 | Full screen on and off. |
| S | Full-screen slideshow, the next picture every 4 s (SlideSeconds in the ini). |
| Ctrl+wheel, +, − | Zoom around the pointer; over the thumbnails it changes their size. |
| 0, 1 | Fit the window / 100 %. |
| Hold the left button | A 1:1 loupe under the pointer on a fitted picture. |
| L, R | Turn the view left or right; the file stays as it is. |
| I | The Info panel with EXIF and the histogram. |
| Ctrl+F, Esc | Into the Filter box; Esc clears it, in the viewer it goes back to the thumbnails. |
| Ctrl+click, Shift+click, Ctrl+A | Select several pictures, Explorer style. |
| Del | Moves the picture (or the whole selection) to the Recycle Bin, always asking first. |
| Ctrl+O, Backspace, F5 | Open a file, the parent folder, read the folder again. |
| F1 | Help. |
What comes next
Sorting pictures into folders
Moving and copying the selected pictures to folders straight from the grid.
Watching the folder
New pictures from the camera show up on their own, without F5.
Requirements
- Windows 10 or Windows 11 (64-bit).
- .NET Framework 4.8, part of Windows 10 since 1903 and of Windows 11.
- No installer and no administrator rights; a single
.exe, settings inMHView.ini. - HEIC without the Windows codec is handled by the built-in library; nothing is downloaded.
- The interface is in English.
Third-party components
MHView's own code is © MHSW.NET. The only third-party code is the fallback HEIC decoder: libheif 1.23.6 and libde265 1.1.3 (both LGPL-3.0), built unmodified into libheif.dll, which is packed inside the .exe and unpacked at run time to %LOCALAPPDATA%\MHSW.NET\MHView. A libheif.dll of your own next to the program takes precedence over the built-in one. The full notice is in the F1 help.