dicon User Guide
Everything you need to know about dicon, the ICO file builder for Windows.
Getting Started
Launch dicon and you are greeted with an empty project containing the default set of icon slots, ready for you to start building an ICO file. The interface consists of:
- Header bar at the top (New, Open, Save, Save As, Language, About, Export Images, and Export ICO buttons)
- Source Images panel on the left (folder browser and image list)
- Icon Slots panel on the right (slot configuration and the slot card collection)
- Status bar at the bottom (command messages, warnings, and a progress indicator during export)
The typical workflow is: choose a folder of source images, drag them onto icon slots, then export the result as an .ico file.
Source Images
The left panel lists the raster images available in your working folder. To populate it, click the Browse button and select a folder containing your source images.
dicon scans the folder for supported raster image files (PNG, BMP, JPEG, GIF, TIFF, and other formats supported by ImageSharp). Each image is listed with its filename, dimensions, and format.
If a file cannot be read or is in an unsupported format, it still appears in the list with a warning indicator explaining the problem.
Folder Summary
A chip below the folder path shows the number of supported image files found (e.g., “7 supported image files”). When no folder is selected, a placeholder prompts you to browse for one.
Icon Slots
The right panel contains the icon slot collection. Each slot represents a single entry in the finished ICO file and specifies a target size and pixel format.
Default Slots
A new project starts with seven recommended slots that cover the most common icon sizes:
| Slot | Container |
|---|---|
| 256x256 PNG | PNG-backed ICO entry |
| 128x128 32-bit | BMP-backed ICO entry |
| 64x64 32-bit | BMP-backed ICO entry |
| 48x48 32-bit | BMP-backed ICO entry |
| 32x32 32-bit | BMP-backed ICO entry |
| 24x24 32-bit | BMP-backed ICO entry |
| 16x16 32-bit | BMP-backed ICO entry |
Adding Custom Slots
Use the Add image slot controls at the top of the right panel to create slots with custom dimensions and formats:
- Width and Height — Each edge can be 1 to 256 pixels. Width and height can be different (non-square icons are supported). When you type a width, the height field auto-fills to match; change it if you need a non-square size.
- Format dropdown — Choose the pixel format for the entry.
The available formats are:
| Format | Description |
|---|---|
| PNG | PNG-backed, 32-bit color with alpha |
| 32-bit | BMP-backed, 32-bit color with alpha (ARGB) |
| 24-bit | BMP-backed, 24-bit color (no alpha) |
| 16-bit | BMP-backed, 16-bit color |
| 8-bit | BMP-backed, 256-color indexed palette |
| 4-bit | BMP-backed, 16-color indexed palette |
| 1-bit | BMP-backed, 2-color indexed palette |
Click the Add button to create the slot, or click Add Recommended to restore any missing entries from the default set.
Slot Summary
A chip in the header area shows how many slots are assigned out of the total (e.g., “3 of 7 image slots assigned”).
Slot Cards
Each slot is displayed as a card containing:
- Preview — A 72x72 pixel thumbnail of the assigned image, or a placeholder showing the slot dimensions and “empty” when nothing is assigned.
- Display name — The slot’s target size and format (e.g., “256x256 PNG”).
- Container type — Either “PNG-backed ICO entry” or “BMP-backed ICO entry”.
- Status badge — A color-coded indicator:
| Badge | Color | Meaning |
|---|---|---|
| Exact size | Green | The assigned image matches the slot dimensions exactly |
| Will resize on export | Orange | The assigned image will be scaled to fit during export |
| Missing | Gray | No image has been assigned to this slot |
| Missing file | Red | The assigned file no longer exists on disk |
| Unsupported | Red | The assigned file is in a format that cannot be read |
Removing and Clearing Slots
- Remove — Deletes a custom slot from the collection entirely. Only available for slots that are not part of the default recommended set.
- Clear — Removes the assigned image from a slot but keeps the slot itself. Available whenever an image is assigned.
Assigning Images
To assign a source image to an icon slot, drag it from the source images list on the left and drop it onto a slot card on the right. The slot card highlights with a blue border while you hover over it to confirm the drop target.
Once assigned, the slot card updates to show a preview of the image, the source filename, and a status badge indicating whether the image is an exact size match or will be resized on export.
You can reassign a slot at any time by dragging a different image onto it. The previous assignment is replaced.
Auto Assign
When your source folder contains images whose dimensions match icon slot sizes, an Auto assign button appears below the folder summary. Clicking it:
- Creates any missing slots that match the dimensions of your source images
- Assigns each uniquely sized source image to the slot with matching dimensions
Auto assign only matches images whose width and height correspond exactly to a slot size. Images that do not match any slot are left unassigned.
Projects
dicon saves your work as .dicon project files, which are JSON text files storing your slot configuration, image assignments, and source folder path.
New
Resets the project to a fresh state with the default icon slots. The source folder, all assignments, and any imported ICO session are cleared.
Open
Opens a file dialog where you can select a .dicon project file or an .ico file. Opening a .dicon file restores the saved project state. Opening an .ico file imports it (see Importing an ICO File).
Save
Saves the current project to its existing file path. If the project has never been saved, a Save As dialog opens instead.
Save As
Opens a save dialog where you can choose a new file name and location for the .dicon project file.
Exporting an ICO File
Click the Export ICO button in the top-right corner of the header bar. A save dialog opens where you choose the output path for the .ico file.
dicon exports all assigned slots into a single multi-entry ICO file. During export:
- Images that match their slot dimensions exactly are written as-is
- Images that differ from their slot dimensions are resized to fit
- Slots with no assigned image are skipped
- Slots whose assigned file is missing or unreadable are reported as errors
A progress indicator appears in the status bar while the export is running. When it finishes, the status bar shows a summary of what was exported, or details any issues that prevented the export from completing.
At least one slot must have an assigned image before you can export.
Importing an ICO File
To inspect or modify an existing ICO file, use Open and select an .ico file. dicon reads every entry in the ICO file and:
- Extracts each image to a temporary folder
- Creates a matching icon slot for each entry
- Assigns the extracted image to its corresponding slot
- Sets the source folder to the temporary extraction directory
From here you can modify the slots, reassign images, add or remove entries, and then export a new ICO file.
Exporting Images
After importing an .ico file, the Export Images button in the header bar becomes available. Click it to copy the extracted images from the temporary folder into a permanent folder of your choosing.
This is useful when you want to save the individual images from an ICO file for editing in an external image editor.
Status Bar
The status bar at the bottom of the window shows:
| Element | Description |
|---|---|
| Status message | A description of the most recent action or instruction (e.g., “Exported 7 entries to app-icon.ico”) |
| Progress indicator | An animated progress bar shown during ICO export |
| Detail lines | Additional error or warning messages shown in red when an operation encounters issues |
Language / Localization
dicon is available in 15 languages:
| Language | Code |
|---|---|
| English (United States) | en-US |
| German (Germany) | de-DE |
| Spanish (Spain) | es-ES |
| Spanish (Mexico) | es-MX |
| French (France) | fr-FR |
| Italian (Italy) | it-IT |
| Japanese (Japan) | ja-JP |
| Korean (Korea) | ko-KR |
| Dutch (Netherlands) | nl-NL |
| Polish (Poland) | pl-PL |
| Portuguese (Brazil) | pt-BR |
| Russian (Russia) | ru-RU |
| Turkish (Turkey) | tr-TR |
| Chinese Simplified (China) | zh-CN |
| Chinese Traditional (Taiwan) | zh-Hant-TW |
Changing the Language
Click the Language button (labeled “Aĉ”) in the header bar. A dialog opens showing all available languages with their native names. Select one and click OK to apply the new language.
On first launch, dicon auto-detects your Windows display language. If your language is not supported, it defaults to English.
About Dialog
Click the ? button in the header bar to open the About dialog. It shows the application name, version, and copyright information. From here you can access this help page, file a bug report, or view the privacy policy.