I am new graphic and web designer. I would like to upload some photos in my website with high quality resolution. I hope you can help me with tips and advice in the proper way of uploading high quality photos in the website.

1. What is the maximum image file size that I can upload to the webpage? I have 2-3 MB image sizes.

2. What is the recommended and best image resolution to use in webpages? Does it make a difference if i have 72 dpi resolution or a 600 dpi resolution image?

3. Does high resolution and high image file size affect the page ranking and performance of the website? if yes, in what way?

4. How can i have a high resolution image with fixed pixel dimension? For example, the image should have 770x200 pixel dimension, can i increase the resolution of the image without changing or altering the dimension? How can i do this in Photoshop?

I appreciate your input and expert advice. Thanks for your help in advance.