No one knows your business, service, or organization better than you, and therefore, your input is absolutely central to the development and/or revision of your online presence. Your success on the web depends in large part on the content that you provide, so your first challenge is to clearly define in your own mind what you would like to present.
Ideally, after you prioritize what you need updated, you would shortly thereafter have ready much of the content to be included. So for example if you want photos replaced, have the new photos on your computer in digital form; if you want to revise wording on various pages, then have the new text content written (at least as first-drafts).
BTW, in regards to your photos, we can use Photoshop to crop, color balance, touch-up, resize, straighten, etc ~ you simply need to have the originals readily available ~ after you send us copies of those original images, we'll do the rest; and in regards to text, once again we can help with editing, phrasing and formatting.
Website construction is like any other service ~ the longer something takes, the more it will cost, so to do a top quality job and yet keep your cost within budget, we need to work efficiently with each other. Having a good idea of what you want, with your new content mostly ready to go, allows us to proceed at a steady pace, which means less time on our end and less cost on your end.
When you hire us, we work for you, so it's our job to do what you tell us to do. If we think there's a more productive way to handle something then of course we will suggest it, but generally you set the direction and we follow your outline. The key is for you to have a fairly clear sense of what you want, so we can make it happen...