You can translate several resources at a time with Sites Translation Tool. This tool lets you view all your sites controls, manage their content in all your available languages and download a localization file, that you can edit offline and upload to update your site content.
What you need to do
You can access the translation tool directly from the Sites Dahsboard, by clicking the Manage Translations option in the three dot menu.
This opens the translation tool where all your site controls are listed along with their values in the languages you selected for your multilingual site.
When you click the Download button you will download an excel file with all the listed controls and languages. Edit the file to add your translations.
After you're finished adding your translations upload the file by dropping it in the upload area or click the button to select your file. Once it finishes uploading, the values for each control are replaced with those in the file.
You can also directly edit the values from your browser.
The tool also lets you filter the controls by pages and search for a specific control.
You can also access the tool directly from the designer to edit one or more controls. To do this, select your site controls right click and then select Manage Translations.
You will be directed to the translation tool where all the selected controls are listed.
Image localization
You can have a different image for each of the languages available for your site. When you're using a link to an external resource you can edit the link to match the link to the image in the desired language.
In case you don't have an external content management resource, you can change your images directly from the Sites Designer.