Storyline SCORM export suddenly much larger than the Storyline project

Hi everyone,

I’m having a strange issue with a Storyline 360 project and I’m hoping someone can help me understand what’s happening.

I have a Storyline project that was originally 206 MB. When I published that version as SCORM, the exported SCORM package was 246 MB.

I needed to get the SCORM package below 230 MB for our LMS, so I started compressing the images within the project.

After compressing and replacing the images, I managed to reduce the Storyline project file from 206 MB to 196 MB.

However, when I published this new version as SCORM, the package unexpectedly increased to around 270 MB.

So the sequence is:

• Storyline project: 206 MB → SCORM: 246 MB
• Compressed/replaced images
• Storyline project: 196 MB → SCORM: ~270 MB

What is particularly strange is that when I checked the published SCORM files, I found that the images were actually being increased in size during the publishing process.

For example, I had an image that was 104 KB in the Storyline project. The Media Library also showed it as 104 KB. However, when I located that same image in the exported SCORM package, it was around 3 MB.

I found this happening with a lot of the images — the file sizes in the published SCORM were significantly larger than the corresponding images in the Storyline project.

I've also checked the Media Library and the largest images currently in the project are around 2.1 MB, so there doesn't appear to be one particularly large asset causing the increase.

I extracted the SCORM package to investigate further. The extracted package is around 300 MB, while the story_content folder is only 6.9 MB, so the majority of the size appears to be coming from elsewhere in the published output.

The really strange thing is that the SCORM export was working fine earlier today. The original 206 MB project exported to 246 MB. It was only after I started compressing and replacing images that the SCORM output started increasing to around 270 MB.

I'm running Storyline 360 on Windows through Parallels on a Mac.

Has anyone experienced anything similar, where images are becoming significantly larger when Storyline publishes them to SCORM, even though the source images in the Storyline project/Media Library are much smaller?

I'm trying to understand why Storyline is increasing the image sizes during publishing and what could be causing the SCORM package to jump from 196 MB to 270 MB.

Any advice would be massively appreciated!

Thanks!