Can you remove software that views image files in Linux?
 

To solve the problem explained below, I am considering removing all programs and software that handle images so that you cannot view images on the computer and .jpeg would be an unrecognizable file. It's impossible to remove the program that views images in Windows since Explorer is that program - a central Windows component, but I wonder if it is possible to use an alternative operating system like linux and remove the programs that handle images without affecting the system.

I need to do this because of the following problem. I had an internet filter installed but it became useless once certain proxy/circumventor sites such as www.ibypass.com were discovered, which allowed access to any website on the internet. Blocking proxy sites does not work because you can type "https" at the beginning of some of these web addresses and the internet filter cannot keep track of the secure browsing. Therefore I want to figure out if you can remove software from linux or other OS that handle images and I might have to switch to a text only browser too.

Your problem is very unusual. Could you be a little more descriptive of the problem? Like are people in a corporate or educational environment viewing things they shouldn't?

I'm just trying to figure this out for home use. I know it's impossible to do this in Windows so I asked here.

You can certainly remove image handling applications from your system. You only need to know which applications you don't want.

However, be careful not to remove dependencies to other programs, for example, if you remove libjpeg, all graphic applications that use it will break, probably including your desktop environment, your browser, and who knows what else.

So be careful if you're not sure about an application or package in your system, ask first.

Okay, so are trying to keep family members in your house from viewing inappropriate material? The only real way to completely disable support for graphics is to remove everything even remotely related to the Xorg graphics sub-system, which basically means dropping all users to a command prompt. Instead, I suggest looking into something like DansGuardian, and download a blacklist. Then, (assuming you have root/admin privileges), you can look at the web history of each user and determine what changes need to be made to the blacklist. When it comes to content filtering, there is no such thing as a magic bullet. You have to stay on top of things and remain diligent.

That's a much better solution than removing graphic related applications. Removing specific software and file associations can be done but requires a bit of knowledge of the system and the relationships between applications. I also recommend a web content filter to the OP.

There isn't a "program" that handles images, but different libraries for different image formats. And just about everything that's not command line relies on them and cannot run without them.

Also, do you realize that everything from your desktop wallpaper to icons and possibley even your GUI controls (depending on the theme) are images?

It seems your issue is two fold. One is content that you are trying to prevent but also personnel control. Without both, it would be difficult to maintain complete control.

I'd agree that a layer 7+ firewall might help. Blocking http and https to only allowed sites may help along with all other ports being blocked.

If they have access to a system they could easily run a live cd or usb or pxe boot to some OS.

This isn't going to work. You could uninstall the image viewing/editing applications, but then your office software, web browsers, graphical file managers, etc can also display image files.

"Blocking http and https to only allowed sites may help along with all other ports being blocked."

Can you really limit https to only allowed sites? I was using cybersitter in Windows and the only thing possible was to block all https or not at all, but you couldn't filter https by sites because the filter was not able to detect secure browsing. Also a "blacklist" can't be perfectly reliable because many new websites are added to the web each day including proxies. The ideal internet filter would just allow all web-sites but only display images on a custom list of allowed sites.

Diantre said, "Removing specific software and file associations can be done but requires a bit of knowledge of the system and the relationships between applications." So maybe my idea is still possible.
An easier solution may just require testing more internet filters until I find one that actually works. I may also try the idea of a text only web-browser.

Yes, on can limit to only a list of sites/ip addresses.

Offering sites like google would break that as it could be used to bypass controls.

Your problem is still with personnel control.

I haven't actually used DansGuardian, but I'm under the impression that it may be what you're looking for. From their website:

It's also possible to create iptables rules to block everything except the sites you want.

I did say that. But I think that I would try the web content filters first, then iptables rules and if everything else fails, I'd try your approach, reluctantly. Don't get me wrong, I'm not saying it's not possible or that you shouldn't do it, it's just that I think dugan is right, even if you remove graphic applications, you still have office applications, file managers and other applications that can display images. And if you remove the libraries these applications use to display images, like libjpeg, libpng or libtiff, many more applications will break in your system, so this procedure is extreme and somewhat error-prone. YMMV.

Whatever you decide, good luck, and if you need help, don't hesitate to ask.

Thanks Diantre,
I know the other programs like office applications will work, but I could get software that controls which applications are allowed to be used on the computer. One other idea that may work could be a text-only browser. I think I'm going to research more internet filters first.