Attachments	PMs	Profile Pic Size	Avatar Size	Signature	Sig Length	Albums
New Users	1 mb	100	120x120, 64k	120x120, 64k	468x75, 65535	400, 300	1280x1024, 100, 3 mb
After 10 posts	2 mb	100	120x120, 64K	120x120, 64k	468x75, 65535	400, 300	1280x1024, 200, 5 mb
After 25 posts	4 mb	100	150x150, 128K	150x150, 128K	500x100, 200K	500, 300	1280x1024, 250, 6 mb
After 100 posts	8 mb	500	150x150, 150K	150x150, 150K	500x100, 200K	500, 400	1280x1024, 250, 16 mb
After 500 posts	16 mb	1000	150x150, 160K	150x150, 160K	500x100, 200K	500, 400	1280x1024, 500, 16 mb
After Dark	64 mb	5000	150x150, 160K	150x150, 160K	500x100, 256K	600, 500	1280x1024, 1000, 64 mb
Certified Tech	64 mb	5000	150x150, 160K	150x150, 160K	500x100, 256K	600, 500	1280x1024, 1000, 64 mb
Admins	no quota	-	150x150, 160K	150x150, 160K	500x100, 256K	600, 500	1280x1024, 5000
Moderators	64 mb	5000	150x150, 160K	150x150, 160K	500x100, 96K	600, 500	1280x1024, 5000, 64mb
Advertisers	64mb	20,000	150x150, 160K	150x150, 160K	500x100, 96K	600, 500	1280x1024, 5000, 64mb

As part of increasing avatar, profile picture and attachment privileges I've created the above chart for reference. After Dark members also have animated avatar and profile picture privileges.

The column above:
Attachments - maximum combined file size images you directly upload into posts
PMs - the maximum number of private messages you can have
Profile Pic Size: maximum dimensions and file size
Avatar Size: maximum dimensions and file size
Signature: maximum dimensions and file size of signature picture
Sig Length: first number of the maximum number of characters in a signature includingBB Code tags. Second number is the maximum number of characters excluding BB Code tags.
Albums: maximum image dimensions, maximum number of images you can have in your albums, maximum combined album image file size

If you fall into more than one category, you get the privileges which are the most generous of the categories you're in.

Don't ask for special treatment, you're not special. Post more to move up in the ranks, or join After Dark. After Dark privileges might be increased in the future, if we bump into image quota issues.

Also, please don't abuse animated avatars, profile pics, etc. Have fun with them, but don't use them to show how much of an ass you can be, because no one likes seeing the same stupid animated signature 5 billion times. Its like a joke, funny the first couple of times you hear it, after that... no so much, lol. While everyone may not like the numbers above keep in mind they have been increased, and try to strike a balance between page load time, more privileges for more active users and disk space.

 

Update 6-17-2015: Since we've been able to expand drive space, the limits have changed (mostly increased):

Attachment Bytes	Private Messages	Profile Image Size	Avatar Image Size	Signature Image Size	Sig Length, bytes & displayable bytes, max lines	Albums: max images, max bytes, max resolution
New Users	4 mb	10 *	120x120, 64K	120x120, 64K	475x75, 64K	400, 300, 3	1280x1024, 50, 4mb
After 10 Posts	16 mb	100	120x120, 64K	120x120, 64K	475x75, 128K	500, 300, 5	1280x1024, 200, 16mb
Classfieds Poster	16 mb	500	150x150, 150K	150x150, 150K	500x100, 200K	700, 500, 5	1280x1024, 500, 20mb
Senior User	100 mb	1000	150x150, 160K	150x150, 160K	500x100, 200K	700, 500, 5	1280x1024, 500, 20mb
Certified Tech	100 mb	5000	150x150, 160K	150x150, 160K	500x100, 256K	700, 500, 6	1280x1024, 1000, 64mb
Avertisers	no quota	no quota	150x150, 160K	150x150, 160K	500x100, 256K	700, 500, 6	1280x1024, 5000, 100mb

* Decreased to prevent PM spammers.

Classified Poster: 30 days and 100 posts, 90 days and 75 posts, 6 months and 50 posts, or 1 year and 25 posts - whichever comes first
Senior User: 500+ posts

We also do not have the same user groups as before which is why you see other differences in the charts.