JPEG or PNG?

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JPEG or PNG?

Postby Koll » Fri Jan 10, 2014 9:15 pm

I am screenshotting a game for a fan game I am trying to make. In the beginning I was saving them as .BMP but I now realise that was a mistake because of the large file size. Keeping in mind I want my game to be a reasonably sized download (not too big) but also have good quality images, what file format should I be saving them as?
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Re: JPEG or PNG?

Postby reneuend » Sun Jan 12, 2014 5:46 am

I prefer PNG over JPG for most non-photo type images. I read that they work best for gradients. I'm not an expert, so we'll see what others have to say on this subject.
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Re: JPEG or PNG?

Postby Stitches » Sun Jan 12, 2014 2:17 pm

AM can't support PNG can it? Or is there a plugin for it... because that would be a ~~didn't mean to swear~~ of a lot better for developing with. :D
http://www.youtube.com/user/MaynardStaly/videos and http://libertycap.webs.com
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Re: JPEG or PNG?

Postby reneuend » Sun Jan 12, 2014 5:37 pm

AM doesn't directly support PNG, which is very unfortunate. PNG would be a much better choice for Hotspot images.

Slightly off topic:
If you ever want to use Image cursors, KeyGuard supports several image types including PNG. When I finish my latest game, you'll see different uses for Image Cursors.
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Re: JPEG or PNG?

Postby Koll » Mon Jul 07, 2014 6:32 am

Resurrecting this thread. Firstly thanks for your replies. Secondly, I am quite shocked that AM doesn't support PNG files. I hope this will be rectified in an update sometime because it seems to be the standard file format for images nowadays. You said AM doesn't directly support PNG files so is there a plugin that will let me use PNG files?
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Re: JPEG or PNG?

Postby reneuend » Mon Jul 07, 2014 2:55 pm

KeyGuard works with numerous image types, but it depends on "how" you want to use them. I would suggest experimenting with KeyGuard plugin.
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Re: JPEG or PNG?

Postby Koll » Thu Jul 17, 2014 8:05 am

reneuend wrote:KeyGuard works with numerous image types, but it depends on "how" you want to use them. I would suggest experimenting with KeyGuard plugin.


Will do, thanks.

reneuend wrote:I prefer PNG over JPG for most non-photo type images. I read that they work best for gradients. I'm not an expert, so we'll see what others have to say on this subject.


With regards to your quote above, what would be best for screenshotting an FMV game? JPEG or PNG?
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Re: JPEG or PNG?

Postby skype6 » Thu Jul 17, 2014 2:32 pm

If you ever want to use Image cursors, KeyGuard supports several image types including PNG. When I finish my latest game, you'll see different uses for Image Cursors.


Can you please explain how to put png file for cursor in keyguard? For me it's a mystery :roll:
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Re: JPEG or PNG?

Postby reneuend » Fri Jul 18, 2014 1:48 am

Have you looked through the KeyGuard documentation?
It explains quite well how to not only build image cursors, but also how to build animated image cursors.
When I build another one for my game, I'll build a tutorial on this.
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Re: JPEG or PNG?

Postby skype6 » Fri Jul 18, 2014 11:39 am

Well, I have to admit, programming is not my stronger side! I know some basic stuff and still learning, but this is a challenge .. If you could make a tutorial: Step by step, I would be enormously grateful :) I still do not know exactly where certain things go and It would help me a lot.
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Re: JPEG or PNG?

Postby reneuend » Sat Jul 19, 2014 4:09 pm

If you haven't found the post already, here is how to build an image cursor. Be sure to let me know if you have any issues.
http://amforums.cloudapp.net/phpbb/viewtopic.php?f=10&t=6751
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Re: JPEG or PNG?

Postby skype6 » Sat Jul 19, 2014 7:21 pm

Great stuff,Thank you :mrgreen:
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Re: JPEG or PNG?

Postby Koll » Sun Jul 20, 2014 6:38 am

reneuend wrote:I prefer PNG over JPG for most non-photo type images. I read that they work best for gradients. I'm not an expert, so we'll see what others have to say on this subject.

Koll wrote:With regards to your quote above, what would be best for screenshotting an FMV game? JPEG or PNG?


Can you answer this question please reneuend? You seem to know a lot about this sort of thing.
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Re: JPEG or PNG?

Postby reneuend » Sun Jul 20, 2014 7:47 am

I would say JPG. PNG is better for smaller images where JPG is better for larger ones. This is just stuff I've read over the years. What I really notice is that PNG is way better with gradients. We do have some members that are way more qualified than myself when it comes to images. I'm a web and Windows developer so images are more of a side topic for me.
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Re: JPEG or PNG?

Postby Koll » Mon Jul 21, 2014 2:33 am

Thanks :)
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Re: JPEG or PNG?

Postby skype6 » Wed Jul 23, 2014 5:55 pm

These things I picked up along the way but they provide a good explanation!

First, there are two types of compression: Lossless and Lossy.

Lossless means that the image is made smaller, but at no detriment to the quality. Lossy means the image is made (even) smaller, but at a detriment to the quality. If you saved an image in a Lossy format over and over, the image quality would get progressively worse and worse.

There are also different colour depths (palettes): Indexed color and Direct color.

With Indexed it means that the image can only store a limited number of colours (usually 256) that are chosen by the image author, with Direct it means that you can store many thousands of colours that have not been chosen by the author.

BMP - Lossless / Indexed and Direct

This is an old format. It is Lossless (no image data is lost on save) but there's also little to no compression at all, meaning saving as BMP results in VERY large file sizes. It can have palettes of both Indexed and Direct, but that's a small consolation. The file sizes are so unnecessarily large that nobody ever really uses this format.

Good for: Nothing really. There isn't anything BMP excels at, or isn't done better by other formats.

GIF - Lossless / Indexed only

GIF uses lossless compression, meaning that you can save the image over and over and never lose any data. The file sizes are much smaller than BMP, because good compression is actually used, but it can only store an Indexed palette. This means that there can only be a maximum of 256 different colours in the file. That sounds like quite a small amount, and it is.

GIF images can also be animated and have transparency.

Good for: Logos, line drawings, and other simple images that need to be small. Only really used for websites.

JPEG - Lossy / Direct

JPEGs images were designed to make detailed photographic images as small as possible by removing information that the human eye won't notice. As a result it's a Lossy format, and saving the same file over and over will result in more data being lost over time. It has a palette of thousands of colours and so is great for photographs, but the lossy compression means it's bad for logos and line drawings: Not only will they look fuzzy, but such images will also have a larger file-size compared to GIFs!

Good for: Photographs. Also, gradients.

PNG-8 - Lossless / Indexed

PNG is a newer format, and PNG-8 (the indexed version of PNG) is really a good replacement for GIFs. Sadly, however, it has a few drawbacks: Firstly it cannot support animation like GIF can (well it can, but only Firefox seems to support it, unlike GIF animation which is supported by every browser). Secondly it has some support issues with older browsers like IE6. Thirdly, important software like Photoshop have very poor implementation of the format. (~Love to~ you, Adobe!) PNG-8 can only store 256 colours, like GIFs.

Good for: The main thing that PNG-8 does better than GIFs is having support for Alpha Transparency.

PNG-24 - Lossless / Direct

PNG-24 is a great format that combines Lossless encoding with Direct color (thousands of colours, just like JPEG). It's very much like BMP in that regard, except that PNG actually compresses images, so it results in much smaller files. Unfortunately PNG-24 files will still be much bigger than JPEGs, GIFs and PNG-8s, so you still need to consider if you really want to use one.

Even though PNG-24s allow thousands of colours while having compression, they are not intended to replace JPEG images. A photograph saved as a PNG-24 will likely be at least 5 times larger than a equivalent JPEG image, which very little improvement in visible quality. (Of course, this may be a desirable outcome if you're not concerned about filesize, and want to get the best quality image you can.)

Just like PNG-8, PNG-24 supports alpha-transparency, too.

I hope that helps!
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Re: JPEG or PNG?

Postby reneuend » Wed Jul 23, 2014 11:20 pm

Thank you for the great explanation.
Of course, this is all about raster graphics and not vector. I think modern games use a cross between the two but I'm not sure. But still, for us AM developers this explanation is more important.
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