I’m not really sorry. You need to know, and I’m not too shy to tell you.
Your images are fat.
They need to go on a big-time diet. Run on a treadmill or something. Stop eating barbeque potato chips drizzled in melted cheddar. Optimize man. Optimize!
Seriously, in today’s day and age! You still aren’t compressing your images? You’re still putting in 12 megapixel images in for thumbnails!?! I sure hope not. You’re not alone, but that’s no excuse. There are TONS of resources out there to help.
Yes yes… you use Photoshop’s save for web and know when to use a GIF vs PNG vs JPG. And you’ve even tried SVG. But wait? You can do more?
YES! There are LOSS-LESS compressions that you can run on top! And you can run them in gulp or just point them at a folder.
Optimize! Compress! Make the web better!
*Psst. Sprite-sheets are a fairy-tale land and are only for those with massive budgets and/or know that the images will NEVER CHANGE.. hehehe