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Home / No thumbnails for the portable version?


Hello, had a look around but can’t see anything about this.

Does the portable version not do thumbnails? I gather it is an option but the PortableApps version just fully installs the program and I don’t remember seeing any options. I found something on the forum in 2011 saying it isn’t possible with the portable version but if Irfanview can do it…

If not, is there a way to change the icon? I’d like something a lot less yellowy.



Yes, thumbnails only work if you install Sumatra (and select thumbnail creation during install step using ‘Options’ button).

In Windows, generating thumbnails works by registering a dll that Windows will call to generate a thumbnail for a given file type.

Only installable version of Sumatra provides this dll, for 2 reasons.

1. Portable version ships as a single executable, for convenience. There’s no room for shipping a dll.

2. The idea behind portable apps is that it doesn’t leave a trace on your system. You can fully remove it by removing the executable file.

To register thumbnail provider we need to modify registry and we can’t allow for the dll to be just deleted by the user without first unregistering it with Windows.

As to changing the icon: there are many programs that allow editing resources inside a Windows program and an icon is just one kind of a resource.

You could create a new icon and use one of those programs to replace the icon inside SumatraPDF.exe.


That’s a pity. Irfanview portable does thumbnails - but perhaps that is different somehow, I don’t know.

Thank you for your detailed reply.


Nope, Thumbnail Handlers are a Windows feature and if IrfanView Portable is registering one on the system then it is not 100% portable or ‘stealth’. Perhaps this doesn’t matter to you, but that is how it works.

@kjk: How about making the DLL available as a separate download for advanced portable version users (“use at your own risk, no support provided” type deal), along with a simple batch file that calls rundll to register/unregister it?


see discussion about an unofficial part working solution by ianas in eBook Thumbnail-Preview Handler Installer for Windows


Given limited time, I have to choose my projects widely. There’ s no indication that many people would benefit from this and if someone is really that determined, they can extract the dll from installable version and register it themselves.


I guess you’re right. BTW, are people free to redistribute just the DLL (and instructions to use it or optionally a batch file)?