Custom CMS or Open Source?
I am building a site for my friend using PHP and MySQL (Or SQLite, I'm still debating.)  The site is aimed to sell photography online with various options.  The backend shows statistics, recent orders, etc. and allows for the client to upload images, crop them in-browser (using javascript and GD), add a watermark to the image, adjust prices, framing options, coupon codes, etc.  Upon uploading an image, the site must also resize the image, allow for a color change or preset filter, etc.  When a person buys an image on the front end, the site will be contacted using paypals IPN, an email will be sent to the buyer and administrator, and things will resume.

The front end will have the home page showing the 10 most recent uploads, 3 pages where the client can enter contextual information, and a gallery link that will show all of the images (with sorting options, such as sort by color, size, price, tag, category, etc.)

When buying an image, the user will be faced with options such as size, frame or no frame, color, signature, etc.  

Given all this information, would it be easier to use a open source CMS (and which one) or design my own.  (I can design a quick system for this site in about a month or so if thats what it comes down to)

What would be the best way to get a project like this taken care of?

Thanks
Custom CMS or Open Source?
===

I am building a site for my friend using PHP and MySQL (Or SQLite, I'm still debating.)  The site is aimed to sell photography online with various options.  The backend shows statistics, recent orders, etc. and allows for the client to upload images, crop them in-browser (using javascript and GD), add a watermark to the image, adjust prices, framing options, coupon codes, etc.  Upon uploading an image, the site must also resize the image, allow for a color change or preset filter, etc.  When a person buys an image on the front end, the site will be contacted using paypals IPN, an email will be sent to the buyer and administrator, and things will resume.

The front end will have the home page showing the 10 most recent uploads, 3 pages where the client can enter contextual information, and a gallery link that will show all of the images (with sorting options, such as sort by color, size, price, tag, category, etc.)

When buying an image, the user will be faced with options such as size, frame or no frame, color, signature, etc.  

Given all this information, would it be easier to use a open source CMS (and which one) or design my own.  (I can design a quick system for this site in about a month or so if thats what it comes down to)

What would be the best way to get a project like this taken care of?

Thanks