gatsby: Number of generated thumbnails seems huge and crashes build in Windows

Somehow a website of mine that had been building without problems, today has failed during build after having added a couple of additional posts

After trying to increase/decrease versions of sharp package and related plugins without success, I just upgraded all packages of my site just to see that both develop and build were failing

Then I just moved out all the site posts and develop again, and it worked again, but without content of course

My hypothesis is that the number of generated thumbnails gets huge at a point that it crashes due to a sort of out-of-memory error

 [====================----------] 13710/20646 439.4 s 66% Generating image thumbnailsException code=0xc0000005 flags=0x0 at 0x0000000000000000. Access violation - attempting to execute data at address 0x0000000000000000
error Command failed with exit code 3221225477.

Then, the question is how is this happening? In the sense that it wasn’t happening 1 week ago without any significant change

Then,

• If I run my site with a bunch of static images and some non-static images, some pages and just 1 post, I have this

498 thumbnails, from ~60 images, I don’t know if it is excessive but doesn’t seem super-excessive

Then if I add a second post that refers to a static image (that was already there), then I have this

747 thumbnails, this must be wrong

Then if I add 3 more posts

1328 thumbnails

Then if I add the 38 other posts, that before compiled well in Netlify, then I have this

7636 thumbnails

which causes a failure when it went by ~2400

All of this is running gatsby clean && gatsby develop, so that cache and public folders are deleted

These are the packages.json (site -> gatsby-theme-B -> gatsby-theme-A)

  "dependencies": {
    "@mdx-js/mdx": "1.5.1",
    "babel-plugin-styled-components": "1.10.6",
    "gatsby-plugin-mdx": "1.0.24",
    "gatsby-plugin-sharp": "2.3.0",
    "gatsby-plugin-styled-components": "3.1.13",
    "gatsby-remark-copy-linked-files": "2.1.30",
    "gatsby-remark-images": "3.1.31",
    "gatsby-source-filesystem": "2.1.37",
    "gatsby-transformer-sharp": "2.3.5",
    "react-share": "3.0.1",
    "remark-slug": "5.1.2",
    "styled-components": "4.4.1"
  },
  "devDependencies": {
    "@mdx-js/react": "1.5.1",
    "gatsby": "2.17.15",
    "react": "16.12.0",
    "react-dom": "16.12.0"
  },

  "dependencies": {
    "@mdx-js/react": "^1.5.1",
    "deepmerge": "^4.2.2",
    "gatsby-image": "^2.2.33",
    "gatsby-plugin-feed": "^2.3.21",
    "gatsby-plugin-google-tagmanager": "^2.1.17",
    "gatsby-plugin-manifest": "2.2.28",
    "gatsby-plugin-offline": "3.0.21",
    "gatsby-plugin-page-creator": "2.1.30",
    "gatsby-plugin-react-helmet": "^3.1.15",
    "gatsby-plugin-robots-txt": "1.5.0",
    "gatsby-plugin-sitemap": "2.2.21",
    "gatsby-theme-A": "*",
    "react-cookie-consent": "2.5.0",
    "react-helmet": "^5.2.1",
    "styled-icons": "8.6.0"
  },
  "devDependencies": {
    "gatsby": "2.17.15",
    "react": "16.12.0",
    "react-dom": "16.12.0"
  },

  "dependencies": {
    "gatsby": "2.17.15",
    "react": "16.12.0",
    "react-dom": "16.12.0",
    "gatsby-theme-B": "*"
  },