The aim of the research conducted in this dissertation is to define guidelines for preparing digital images in systems that generate content intended for display on websites and for printing on paper. Preparing a photograph for publication in a web environment involves optimizing the file to achieve the optimal balance between quality and file size. The key optimization step involves reducing the number of pixels that make up the image, followed by compressing the image data using a selected algorithm. The expected guidelines were obtained through qualitative and quantitative examination of relevant graphic formats and compression metrics, as well as by determining the optimal settings for creating images for the two aforementioned different application scenarios. Optimizing images for web and print requires a special approach due to the different characteristics of the end media. While web optimization focuses on transmission speed and on-screen display, high resolution and detail are crucial for printing. Therefore, it is important to adjust compression settings and image resolution according to the specificities of each medium. Additionally, the research identified optimal compression methods and file formats that ensure minimal loss of image quality. The combination of qualitative and quantitative analyses has facilitated the development of concrete guidelines to streamline the process of preparing digital images for various types of publications. Two graphic file formats were considered: JPEG and WebP. JPEG has been used for many years and, despite the existence of newer formats, it is still frequently used due to its widespread support and ease of use. On the other hand, WebP is a newer format developed to improve image compression efficiency and web page loading speed. According to previous research, WebP format is more advanced than JPEG in terms of capabilities and image compression optimization, a finding supported by this dissertation. The research extensively analyzed the characteristics of both formats across various aspects, including file size, image quality, and loading speed. The results confirmed that WebP format provides significantly better compression with minimal loss of quality compared to JPEG. Moreover, WebP stands out for its optimization capabilities for web environments, making it an attractive choice for digital content intended for online display. This dissertation provides further confirmation that WebP format is promising and could become the standard format for web graphics in the future. Special emphasis was placed on considering the impact of resolution and compression on the subjective perception of image quality, as well as the impact of optimization on colorreproduction and file size. Subjective evaluation methods are the most reliable means of measurement since the human visual system is the end recipient of visual information. Such subjective assessment based on observer perception plays a crucial role in visual communication systems. The research employed various subjective evaluation methods, including participant ratings and visual tests, to gain deeper insights into the perception of image quality in different scenarios. The results showed that even small changes in resolution and compression can significantly affect viewers' perception of image quality. Furthermore, optimizing resolution and file size are crucial factors in achieving an optimal balance between visual appeal and data transmission efficiency. Understanding the subjective aspects of image quality is essential for developing effective optimization strategies and improving user experience in digital media. To scientifically establish facts upon which relevant conclusions could be unambiguously and comprehensively drawn, a new experimental method was developed to examine the qualitative and quantitative characteristics of graphic formats on a large number of samples, encompassing subjective and objective indicators of image reproduction in the considered environments. The methodology presented in the experimental section of the work includes a series of easily replicable steps aided by developed software support for automating complex tasks. The following research hypotheses were formulated: H1: In the context of image display on a monitor screen, image quality will be perceived as high when the number of pixels constituting the image is greater than the number of pixels that fit within the frame in which the image is displayed. H2: It is possible to significantly reduce the size of the image file by combining resolution reduction optimization with compression, while maintaining high subjective perception of quality and accurate color reproduction. H3: Optimizations performed in the context of image display on a monitor screen are applicable to image preparation for printing, while maintaining a roughly equal high subjective perception of quality between optimized and unoptimized printed images. Additionally, anticipated and expected scientific contributions are outlined: C1: A new experimental method for examining the qualitative and quantitative characteristics of graphic formats on a large number of samples, encompassing subjective and objective indicators of image reproduction in the considered environments. C2: Guidelines for graphic preparation of digital images in systems generating image content intended for two different environments, digital (websites) and printing.C3: Determination of optimal resolution values and compression levels in the process of graphic image preparation using JPEG and WebP format for modern multimedia environments. The conducted research confirmed all predicted hypotheses, successfully achieved all expected scientific contributions, and accomplished the goal of the doctoral thesis, i.e., defining guidelines for graphic preparation of digital images in the considered context.