The theme widths are not to narrow, these are optimised and set for the majority of online visitors, with the changing ways a website can be viewed, like web books and mobile devices, a theme width just under 1000px and images around 600px wide will get a high percentage of visitors.
No point in uploading photographs where a lot of visitors only see part of the image and scroll bars, unless they have hi-res monitors.
Look for a photoblog theme,these often save time, and find a batch processor like Photoshop > Scripts > Image Processor for resizing your images by folder.
Look at the nextgen gallery plugin as well, this allows you to use shortcodes etc:
If you are a Windows user look to use "Windows Live Writer", this is free software that will resize your images for you, so you can prepare posts offline and publish them from your desktop, no need to visit the admin area.
Enter a couple of photography sites URL's, ones with large images through, Googles Browser Size adjust the browser windos and see what percentage of visitors see what parts of the websites.
Google Browser Size is a visualization of browser window sizes for people who visit Google. For example, the "90%" contour means that 90% of people visiting Google have their browser window open to at least this size or larger.
This is useful for ensuring that important parts of a page's user interface are visible by a wide audience. On the example page that you see when you first visit this site, there is a "donate now" button which falls within the 80% contour, meaning that 20% of users cannot see this button when they first visit the page. 20% is a significant number; knowing this fact would encourage the designer to move the button much higher in the page so it can be seen without scrolling.
To view your own Web site with this same visualization overlaid on it, simply type its URL into the "Enter URL here" textbox at the top of the window and click Go.