i am still preparing my notebook for the upcoming wolfram conference and i wanted to place some illustrations and graphics from a variety of sources into the notebook on my macbook air. but when i grab a jpeg or png and move it over onto the notebook nothing happenes.

here's what i figured out to do in order to get the graphic into the notebook (this is very badly expressed becuase i don't the proper words to use, so someone might want to rewrite it to make it clearer):

i use command-shift-4 to create a screenshot of the graphic i want to put in the notebook.

i grab the screenshot and move it onto the notebook to the location i want to put it in and release the screenshot which then goes into a cell in the notebook, aligned on the left side.

i click on the cel bar on the right, then open the FORMAT menu, scroll down to Text Allignment and click on Align Center which centers the graphic.

i then increase or decrease the size of the graphic by clicking on it and resizing it.

i apologize for the vagueness of the above description but i'm a paper and pencil theoretical physicist and am only familiar with the core part of the Wolfram Language and not anything else in Mathematica (i don't even kow how to create or even use a CDF - actually i don't even know what CDF stands for ).