AndrewTaylor
18 May 2004, 16:13
In response to the occasionall call for the file size limit to be upped, as well as the occasional poorly compressed JPEG image, I thought I'd show you how to fit a picture into 100kB. Images can't be over 468x468 pixels anyway, so usually 100kB should be plenty. I never drew an Apathy comic that went over 21kB, for example. The trick is to make the file the right type. The following filetypes are allowed for attachment to posts here: bmp doc gif jpe jpeg jpg mid pdf png psd txt zip. The bold ones are image formats.
THE HAPPY, HAPPY SHORT VERSION :)
If you have drawn a cartoony image, save it as a GIF or an 8-bit PNG, but not using Paint. If you have drawn a "realistic" looking image, or you can't make a PNG or GIF look right, use JPEG.
THE LONG VERSION
BMP and PSD are uncompressed - in fact PSD files store a lot of excess information you don't really need people to see unless you're making a webkit or something. BMP is good for flags and graves, but not much else (as far as the forum is concerned).
JPEG, JPG, and JPE are all the same. They're the "blocky" images. They're very small, but the cost of this is that they distort images. Some programmes allow you to control the compression:quality ratio when you save a JPEG image - this can bu useful when there's a specific size milit as there is here. Most JPEGs which fit into the 468x468 pixel limit will be less than 100kB, but if they aren't it is possible to compress them further if you're using a programme like Photoshop, the GIMP (http://www.gimp.org) (but not Paint). If you do a Google search for "GIMP" please make sure you have moderate safe-search on ;) The way JPEG distorts your image won't be very visible on photographs or CG images. Do not, under any circumstances, save an image as a JPEG if you want someone else to colour it for you. They'll hate you for it. All JPEGs are 24-bit colour.
GIF is an exclusively 256-colour format. If you have a photograph, or lots of gradient fills in your image it might not show up well in GIF format, but if you have a cartoony image it is ideal. (I used GIF for Apathy.) GIFs are "run-length encoded", which means that large blocks (or more accurately, long horizontal lines) of one colour take up much less space than a small, intricate image. This also means you can save some filesize by turning off error diffusion and/or dithering. GIFs can also be animated for good measure (for avatars, say). Paint, however, is very bad at saving GIF images. If you use something like Photoshop, Paint Shop Pro, or the GIMP, you can customise both the number of colours (2, 16, 256, and maybe some other numbers are available) and which colours they are. (In the Apathy comics I only used 15 colours which made the file sizes tiny.)
24-bit PNG is a lossless compression format - which means it makes images slightly smaller than raw bitmaps (BMP), but stubbornly refuses to throw away any information. This rather limits how far it can compress your image, and therefore it is only useful if the image quality is of great importance. This sort of image quality is very rarely nessecary on the style of are seen here. (No offence ;)).
8-bit PNG is like a GIF file, only frequently it is smaller (thanks to its lossless compression). Just make sure you're not using 24-bits, or else your file will come out huge. This format only allows you to use 256 colours, but you get to choose which (or, more likely, your art package will chose the best ones for you after seeing your image), so 256 is usually plently. PNG also has fewer royalties-based problems than GIF, but again that doesn't really matter for our purposes..
IF ALL ELSE FAILS
If all else fails, and your image just won't fit on the forum, you can always link to it. If you just have one image to show us, then there are websites like http://imageshack.us that allow you to upload images to their webspace, or if you're going to be showing us lots of art, you might want to register an account somewhere like http://www.deviantart.com so you can keep it all together and manage it better.
THE HAPPY, HAPPY SHORT VERSION :)
If you have drawn a cartoony image, save it as a GIF or an 8-bit PNG, but not using Paint. If you have drawn a "realistic" looking image, or you can't make a PNG or GIF look right, use JPEG.
THE LONG VERSION
BMP and PSD are uncompressed - in fact PSD files store a lot of excess information you don't really need people to see unless you're making a webkit or something. BMP is good for flags and graves, but not much else (as far as the forum is concerned).
JPEG, JPG, and JPE are all the same. They're the "blocky" images. They're very small, but the cost of this is that they distort images. Some programmes allow you to control the compression:quality ratio when you save a JPEG image - this can bu useful when there's a specific size milit as there is here. Most JPEGs which fit into the 468x468 pixel limit will be less than 100kB, but if they aren't it is possible to compress them further if you're using a programme like Photoshop, the GIMP (http://www.gimp.org) (but not Paint). If you do a Google search for "GIMP" please make sure you have moderate safe-search on ;) The way JPEG distorts your image won't be very visible on photographs or CG images. Do not, under any circumstances, save an image as a JPEG if you want someone else to colour it for you. They'll hate you for it. All JPEGs are 24-bit colour.
GIF is an exclusively 256-colour format. If you have a photograph, or lots of gradient fills in your image it might not show up well in GIF format, but if you have a cartoony image it is ideal. (I used GIF for Apathy.) GIFs are "run-length encoded", which means that large blocks (or more accurately, long horizontal lines) of one colour take up much less space than a small, intricate image. This also means you can save some filesize by turning off error diffusion and/or dithering. GIFs can also be animated for good measure (for avatars, say). Paint, however, is very bad at saving GIF images. If you use something like Photoshop, Paint Shop Pro, or the GIMP, you can customise both the number of colours (2, 16, 256, and maybe some other numbers are available) and which colours they are. (In the Apathy comics I only used 15 colours which made the file sizes tiny.)
24-bit PNG is a lossless compression format - which means it makes images slightly smaller than raw bitmaps (BMP), but stubbornly refuses to throw away any information. This rather limits how far it can compress your image, and therefore it is only useful if the image quality is of great importance. This sort of image quality is very rarely nessecary on the style of are seen here. (No offence ;)).
8-bit PNG is like a GIF file, only frequently it is smaller (thanks to its lossless compression). Just make sure you're not using 24-bits, or else your file will come out huge. This format only allows you to use 256 colours, but you get to choose which (or, more likely, your art package will chose the best ones for you after seeing your image), so 256 is usually plently. PNG also has fewer royalties-based problems than GIF, but again that doesn't really matter for our purposes..
IF ALL ELSE FAILS
If all else fails, and your image just won't fit on the forum, you can always link to it. If you just have one image to show us, then there are websites like http://imageshack.us that allow you to upload images to their webspace, or if you're going to be showing us lots of art, you might want to register an account somewhere like http://www.deviantart.com so you can keep it all together and manage it better.