# File types preferences

Opera handles some file types itself, such as Web page documents. Others are passed on to plug-ins and external applications, or just saved on your computer. The File type preferences let you control Opera's behavior when it encounters different file types.

## File identification

When you click on a link in a Web page pointing to a file, the server tells the browser which MIME type the file has. For instance, text/html is the MIME type for a normal Web page.

In most cases, identifying by MIME works just fine. However, quite a few misconfigured Web servers report incorrect MIME types. The two MIME types that are most frequently misreported are application/octet-stream and text/plain.

If Opera seems to perform a different default action than what you have configured it to do, you can identify files with these two MIME types by file extension instead.

## Setting default actions for file types

Opera comes with a host of pre-set, recommended file types and default actions. Sometimes you may want to change the default action, or add new file types which are not predefined.

### Adding a file type

1. Click
2. Enter the MIME type you wish to set an action for, and make sure you know the exact MIME string involved
3. Enter the file extension associated with the MIME type -- you can specify multiple extensions separated by commas (for example "jpeg, jpg, jpe")
4. Select what Opera should do when you click on links to files of this type
5. Click

### Editing a file type

1. Select the MIME type in the list you wish to edit
2. Click
3. Make changes like when adding new file types
4. Click

Note: Tampering with MIME types may have unwanted side-effects, so be sure you know what you're doing.

### Deleting a file type

1. Select the MIME type in the list you wish to delete
2. Click
3. Confirm that you want to delete the type

Note: Deleting MIME types may have unwanted side-effects, so be sure you know what you're doing.

### Actions explained

Open with Opera | Opens the file using Opera itself. Opera can display text and several markup languages, images and video formats. Be sure that Opera can display a certain file type before choosing this setting.
Save to disk | Downloads and saves the file on your computer. You can also specify a folder to put all files of this type into (for example store all zip files in $HOME/download/zip).
Open with other application | Specify explicitly which external application you want to use. You can also choose to pass the file address directly to the application. This is very useful with streaming multimedia.
Use plug-in | Here you select which plug-in you want to use for this MIME type. Normally, you will not have to change this setting as it is handled automatically by Opera.
Show download dialog | Lets you decide in each individual case. Opens a dialog where you can decide whether to open the downloaded file, or just save it to open later.

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