binary data (php/mysql) - comments wanted

I've got my script working with PHP 4 and storing binary data (JPGs and GIFs) in a mysql db for m,y personals program I'm writing. When all is said and done, I expect an average of 700-1000 pictures to in the db at any given time, with each picture averageing about 50KB. What, if any reliablity/preformance problems am I going to introduce witth using this amount of binary data in conjunction with mysql/php4? Would I be better off having my PHP script upload the file to a directory and then storing the link necessary to retrieve that file in the db and subsequently outputting that to the html page generated? Thanks for all your comments/suggestions. Jon