In several themes, including MistyLook, you can upload a custom header image (full list here). When your image includes the blog title and tagline, the standard ones that show up above the image are redundant; for that reason, some themes include a “Hide Text” option. Unfortunately MistyLook doesn’t. Deleting the title is highly inadvisable googlewise, so you’ve got to hide it. Two ways to do that (without the paid CSS upgrade, that is):
A. If you want to hide the title and the tagline, but not the RSS links, copy and paste this in a text widget:
<div style="position:absolute;width:60%;height:44px;top:12px;left:10px;background-color:#fff;"></div>
This will produce a white strip that will cover the title and the tagline.
(If your title is extremely long, you may need to increase the width percentage.)
B. If you don’t want the RSS links either, make your image 760 x 243 pixels, upload it via Media > Add New, copy its URL; copy the following code, fill in blog URL and image URL, paste result in text widget:
<div align="center" style="position:absolute;width:100%;top:10px;right:0;">
<a href="BLOG URL HERE"><img style="border:none;" src="IMAGE URL HERE" /></a>
</div>
This will produce a header image that covers the whole title area.
In both cases, if you have other text widgets in your sidebar, add the code into one of them. If you have no other text widget, activating one for code A or B alone will leave an empty grey rectangle in the sidebar, so you’ll have to add some extra code to hide that rectangle as well – see end of this post.
Note: Both solutions calculated under the assumption that you’ve got both a title and a tagline. If you’ve typed a title but have deleted the tagline in Settings > General, the title area will be shorter; in that case, height in solution A must be 34px, and image in solution B must be 760 x 229.
https://wpbtips.wordpress.com/
wordpress tips 
Hey I would love to hide my title and tag – I’m using the theme Pressrow.. would you be able to help?
Thanks!!
Posted by alliecakes | April 30, 2010, 22:35@alliecakes: The workaround described under A in this post involves the use of position absolute; see here what that is, and here why you can’t use it in Pressrow to hide the title.
You can go to Settings>General and delete the blog title and tagline (but this is bad for search engines), or you can switch to a theme that features the “Hide Text” option – list here.
Posted by Panos | May 1, 2010, 09:27