Having the things defined for your site will depend on a few factors.
Browsers on mobile devices like phones won’t be the same necessarily vs tablets, monitor screen resolutions etc….
You can certainly define a size and most things will “resize” on the browsing app.
You can do this with html code and/or CSS code in most cases. Do you have a graphics program to resize your images with?
Even though apps are built on standards, they can still interpret differently. Firefox vs internet explorer vs safari vs etc etc ….
You need to define what problems you see in the different apps and build your CSS code to meet the various differences.
Let us know more about what sizes you want for your images and details about your browser or other browsers and how they show your site and I’m sure more suggestions will folllow.
Scroll bars can be done in CSS and a few other methods as well. They used to show on frames, but you should think about how you’ll want the pages to show content and build the code either on the page itself, or in CSS file, etc etc..
Happy to help more if you want.
Matt Geier
(Video Networking Solutions Expert)
(Creative Design Workflow Consultant)
(Social Media Networks Consultant)
(Technical Video Industry Sales Consultant)