[oldfriend]

Are you able to read the JPEG code, like on a banner?

Just curious. How does the web browser know it is showing a banner?

From the HTML code we copy and paste, there has to be a lot more code we are not seeing.

Where are the specific dimensions and images on a 460 x 60 banner located?

I understand we upload the code to a server but there has got to be some extra code somewhere for the specific banner.

Is the specific banner code written in C++ or something similar? (That the computer automatically adds.)

I use to work with Visual Basic and every single image was stored within my VBasic program.

Oldfriend

[Sam]

I was going to post this yesterday but it became too complicated. I want to keep this succinct but feel free to ask below if I haven't fully explained something.

Basically think of JPEG as a file format. It's binary and produces compressed image files. Here's another image format, SVG. The below produces a rectangle. The dimensions are easily visible with a width and height.

Code: Select all

<svg>
   <rect width="300" height="100" style="fill:rgb(0,0,255);stroke-width:3;stroke:rgb(0,0,0)" />
</svg>

Somewhere in the JPEG code will probably be the dimensions of the overall picture.

When your browser loads the index html page, it scans it and finds (usually) that there are a bunch more objects it needs (e.g. the CSS, Images, JavaScript). It sends out simultaneous requests for those objects and displays them to you.

Any Turing complete language can produce/ write JPEG. Python used to have a module for it inbuilt. C, C++ and others have libraries for encoding and decoding... e.g. http://libjpeg.sourceforge.net/.