Image resizing

My research into digital image resizing for the web led me to a great site, Bob Atkins Photography. Finally I found something about this topic that is easy to understand and my questions were answered.

Self taught artist gave great advice when she said to change the pixel height and width. When you display a digital image on a monitor using a web browser the only thing that determines the size of the image when you enlarge it for viewing is the width and height of the pixels. I was surprised to discover that all other data in the image file is ignored, even resolution (ppi data). By fiddling with Adobe Photo Shop, I discovered that changing the height and width in pixels also produces a smaller file size (kb). That makes sense. The aim is to size the image so that when you click on it to enlarge it, it fills the computer screen without "going over" and to have it load quickly. Resampling your image to 640 by 480 pixels works well with most monitor sizes.

It seems I was mistaken when I thought that resizing would affect the amount of detail visible in my image on the web. The smaller the file size the less detail available when you print the image. The proof is in the pudding:

600 pixels wide

2232 pixels wide

What did I learn by comparing these two images?

• no difference in the amount of detail visible
  
• both are the same physical size in the post
• can't tell how large they will be when enlarged until I publish the post

In addition

• decreasing pixel height and width affect the size of the image when you enlarge it
• decreasing pixel height and width affects how quickly an image loads
  

Novice needs help

In Between (2008) Mixed media on cradled panel, 10 x 30

Today I'm experimenting with the file size of the images I upload to my posts. I am such a novice when it comes to anything having to do with digital output. While I can manipulate file sizes, I really don't have a firm understanding of the effects of these changes apart from the obvious that you lose detail. Is there an optimal size to use in your posts? What other factors should I be aware of? I'm hoping for comments from my readers to add to my expertise in this area. The top image is at 252 KB while the second one is 1.0 MB.

I have an additional problem with photographing my work. There is usually an element of subtle texture in it as is present in the right side of this work. Often these areas are quite dark which adds to the difficulty of capturing these subtle areas. Any tips to help with this problem would also be welcome.