Hi Max and Sander,
On which version of PixInsight are you seeing this behavior? It was a Windows-only issue that I fixed in version 1.5 (or that was the intent).
I can't reproduce it on 1.5.2; the file type selection is honored in all cases.
Francisco, what you say about selecting .tif instead of .tiff is a know problem, but it is, AFAIK, impossible to fix. This happens on Windows when you have the "Hide extensions for known file types" (Ocultar extensiones para tipos de archivo conocidos) option enabled on Windows Explorer. With this option enabled (and it is enabled by default), Windows hides file extensions not only to the user, but also to applications that allow the user to select files using native file dialogs. In this way, PI has no way to know the exact file extension you typed in; it can only guess a file type from the selection you made on the file type combo box of the Save As dialog.
This "hide extensions" option is one of those things that really make me dislike Windows. I cannot understand what this option is intended for, other than creating problems. I see no point in hiding something as essential as a file extension.
I strongly recommend, when possible, using multiplatform file dialogs in PixInsight on Windows, instead of native file dialogs. To enable multiplatform file dialogs, do the following:
- Select Edit > Global Preferences.
- Select File I/O Settings (left panel).
- Uncheck the "Use native dialogs" option.
- Press F6 to execute globally.
Behavior of multiplatform file dialogs is 100% predictable and issue-free; they are preferable to native Windows dialogs, in my opinion.
Anyway I'll try to detect and fix any pending issues with native Windows file dialogs. Thank you for your reports.