What is the best format for pictures?

[XCorvis]

Woah, calm down.

Image size does not equate to file size. An image that appears very small might actually be quite large in terms of the amount of data it requires. You're probably making very high-quality images. The setting you're looking for is labled DPI (or possibly PPI), meaning dots per inch (or pixels per inch). I bet it's somewhere between 300-600. Change the physical dimensions to what you want, the reduce the DPI to 72. This will dramatically decrease the file size. Now save the file as a jpeg or png. (Don't use gif, it's not free.)

Jpeg and png file formats have built-in file compression, to make the file size smaller. However, Jpeg compression is lossy, meaning it throws away data to make the file smaller. PNG compression is lossless - it keeps all the data.
If you use jpeg, choose the compression level you want, but know that the more you compress, the worse the image looks. Put it at 90% to start, see if the image looks OK. Now check the file size. (On Windows, right click on the file and select properties.) If the file size is OK and the image quality is OK, upload it. Otherwise, go back and save it with either increased or decreased compression. I don't know what the file size limits on ENWorld are.

For png, just save it and check the size. If it's still too big, go back and reduce the dpi again.

If you've already used image compression with a jpeg file make sure you DON'T use it for anything else. Toss it and go back to an earlier saved version. Once you save with lossy compression, you can't ever improve the quality, so make sure you only use it for your final version. (It's ok to use a file saved with no compression or "lossless" compression - it's still at the original quality level. PNG is lossless.)

Edit: corrected, png is lossless, not lossy.

 

[XCorvis]

So its-
JPEG
BMP
PNG

Jpeg is an old, widely accepted open standard. Anything that can show images can show jpegs. It has built-in lossy compression. It doesn't show line drawings and text as well as other formats like PNG and GIF. The newer JPEG 2000 standard is better, but it's not widely supported.
BMP is a very basic image format. It has no compression and file sizes are very large. Browsers may or may not show it.
GIF is a protprietary format. Compuserve owns it and tried to sue a bunch of people for royalties when they were using it. It has built-in lossless compression. Technically, it's a fine format. You can use it for animations and transparent images, and all browsers will see it. But don't use it - it's falling out of favor.
PNG is a newer format, created specifically to replace GIF. It can do everything GIF can and more, plus it's free. It has built-in lossless compression. Modern web browsers (IE 6, Mozilla, Netscape 6+) can show PNG, but older versions won't. (IMO, this is not a shortcoming, but I'm a technophile.)

My personal opinion is that you should use PNG, because it's better and free, but you could also use JPEG if you really wanted to.

Oh, and instead of Photoshop, use GIMP ( http://www.gimp.org/ ). Bad name, good program.

 

[Acquana]

Goodness! I hadn't realized how much trouble you were having! XCorvis has good advice, though I have never used Gimp, and I am under the belief that Photoshop is what created the gods ... Yeah, just make sure you've got 72 dpi, anything higher is sheerly for printing it on paper as opposed to looking at on a screen. Plus, most people's monitors only have from about 600 to 800 pixels on the y axis. Making an image much, much larger than someone can comfortably look at it on their screen can be frustrating for the reader.

Acquana- nice work. I checked out your thread.

Why thank you. ^_^ Always appreciative of more hits.

 

[megamania]

Let's try this then.....

 

[megamania]

so dpi is not the quality of the image but the pixels. I thought that was the quality.

Anyhow. That was it. I just now need to figure out a few more tricks and I hope to do either a "comicbook" format, a "daily" strip or something between my current typed stuff for story hours and these images.

Thankyou everyone.

As you can tell, when my folks told me to consider computers as a major back in the late 80's I opted for art instead. sigh.......

 

[ml3]

image formats

so dpi is not the quality of the image but the pixels. I thought that was the quality.

Anyhow. That was it. I just now need to figure out a few more tricks and I hope to do either a "comicbook" format, a "daily" strip or something between my current typed stuff for story hours and these images.

Thankyou everyone.

As you can tell, when my folks told me to consider computers as a major back in the late 80's I opted for art instead. sigh.......

dpi is the number of pixels. The more pixels per inch, the more information the image hold, thus better quality as the dpi goes up.

Computer monitors can only display at 72 dpi, so there is no sense in going higher unless you want to enlarge your image without losing quality.

Here's the long and the short of it:
Print resolution is generally 150 dot per inch and up. Since your monitor canot fit 150 dots in to an inch, it makes the "inches" bigger to accomodate them. That is why higher res images get bigger on your screen. You have to look at both dpi and physical dimensions. Double the dpi and your image dimensions double on screen, etc.

Jpg (or jpeg) is used for photo quality images. It handles gradients and color shifts much better than gif. It compresses image size by optimizing colors. While you're eye may not distinguish between two similar shades of blue, your computer can, and rendering both colors takes up memory. Jpgs replace one of those shades with the other. Your eye can't see the difference, the computer only has to render one color instead of two, the file size is smaller and everyone's happy.

Gif has far fewer colors available to it than jpg, thus it handles gradients and shading poorly and tends to pixelize. It is better suited to solid color images like non-shaded cartoons, logos, text, etc. It does have tranparency, but it is an on or off proposition. You can't have a pixel 50% transparent, so often gifs tend to have a "fuzz" around them where a transitional color exists between the inner and outer borders. This can be fixed, but it takes a little more effort. You can also animate gifs. My avatar is an animated gif. Had it not been animated, I would have made it a jpg instead.

PNGs on the other hand have the color range of jpgs with variable opacity. You can have any number pxels with gradual transparency, so the transitions are smoother. All together it is a superior format but it is still not widely supported, so I tend to stay clear. I'm sure that will change soon enough.

BMP is ok for print and internet display, but it is somewhat antiquated and not as good as the alternatives in my oppinion.

Tiff is for print. Period. It is intended for high resolution display. It does have the ability to compress images somehwat for screen display that are smaller than a PSD, but the files are still much larger than jpgs.

So, for Internet displays, if it has any shading, gradients or color variations, use jpg. If it is solid, primary colors; print or clean black and white, or needs to be animated, try gif.

 

[megamania]

Since I am still experimenting with imagery on the computer I opted to go with a combo of text and pictures for a Storyhour. I may still do my comicbook or strip but later. Perhaps with Strikeforce: Morituri II which I will possibly begin this fall.


Check out what I have done at THE PATHFINDERS

check link at top of thread within my signature.

 

[Azul]

I seem to recall that GIF only does a 8-bit colour palette (well, technically it uses customized 8-bit palettes to emulate something like 24-bit colour). JPEG uses a real 24-bit colour palette. PNG also uses real 24-bit colour IIRC (or would it be 32-bit colour if you count the transparency gradients?).

Images that are rich in colour (like photos and such) often look good as GIFs if they are mostly images with predominantly many shades of one colour (e.g. a mostly green forest scene, a mostly blue scene of the see and sky). Pictures with lots of colours force the GIF to divide its palette too much and then you see lots of ugly banding effects and unnatural colouration. To my understanding, PNG (the new rival lossless format) doesn't suffer from this.

If your images are mostly line art or something like that, avoid JPG. It tends to fuzz up the images. PNG is ideal for those. If you have smooth colour transitions like a photo, then JPG is great. GIF's only real advantage over PNG is that older software supports it better. Pretty much all recent software supports PNG.

 

[sirhonorable]

Jpegs are a good format for posting on the internet, but NEVER EVER use them if your sending them to get printed or published. Every time you save a JPEG it re-compresses it and over time you get image data loss. TIFFs are the way to go if at all possible.

If you wanna see how much damage a JPEG does to an image, open up MSPaint and make a few different colored squares and circles, then save it as a JPEG. Then, quit and re-open the file and use the fill bucket to change the colors of the shapes, then youll see how much jpegs suck.

The only time I would use jpegs is if i was putting a low-res image on a webpage. All other times, TIFF is the way to go.

If tiffs arent available, use a BMP, 2nd best choice.