Images on webpage..how???

I have been sturdying webpage design and html and css for about a month now and im planning on going to school for this but im trying to learn as much as possible before i start school.Ok my problem is this....i use the simple image tag to insert an image into the page i do believe its <img src="image name.gif or jpg"> and then i may add some attributes and what not.But the problem is...the picture will never show up when i try to view the page i meen its there with the description and all that but all i get is an x in the upper left corner...can anyone help me or tell me what i am doing wrong?Please and thank you.

Ok sorry i kind of got that wrong and left out a little bit of info.Ok i have my web site pages all in the same folder and i also have another folder inside this folder called images which is where i store al my images for the website so the html tag i use to insert one of my images is this <img src="images/picure name.jpg" alt="description" border=3 align=center hspace=25 height="300" width="300"> what am i doing wrong lol i have been trying to figure this out for a week now!