If a website header made in the image format, the logo can be placed on top of the existing images in any graphics editor. This is the easiest option that does not require editing pages. To use it, find the image file caps on the site server and upload it to your computer. Then open it using a graphics editor - for the upcoming operation quite enough opportunities standard Paint Windows.
Place on top of the open clip art logo image in Paint for this purpose the item "Paste" in the drop down "Paste". The mouse, drag the logo to the desired location of the background image, change the image dimensions and save the result by pressing Ctrl + S. Download the file caps with logo to the server, replacing the original file, and the operation is completed.
To insert the logo in the HTML code of the page more convenient to use a graphical (WYSIWYG) page editor, which is available in most content management system. Open the desired page in this editor, click the location to which you want to place the logo and click insert image from the menu. On the screen you should see a dialog where you specify the storage location of the logo file in the computer. Depending on the editor, in the same dialog may be fields for entering additional parameters - the size of the image of the indentation from the adjacent page elements, etc. All fill in, click OK, and then save the edited page.
In the absence of the ability to use the page editor to make the tags in the source code will have to "manually". To do this, find the file on the server for the page you want, download it into your computer and open with any text editor - e.g. Notepad. This operation requires some knowledge of the typesetting language of the hypertext - you need to find the HTML code for the correct place to put the tag logo. The tag in the simplest case, one can write, for example:

<img src="logo.png" />
Adding the line in the source code, save the page and replace the edited file is stored on the server the original. Then load back the image file - for example from the previous step, this file should be called logo.png and stored in the same folder of the server where you placed the edited page.