The objective of this work was to apply computer image analysis to digital images taken with a digital camera to monitor the growth of white rot fungi (Trametes gibbosa and Trametes versicolor AG613) and evaluate their performance in degrading synthetic dyes (fuchsin, crystal violet, congo red, malachite green, and methylene blue) at three concentrations (10 mg \(L^{-1}\), 50 mg \(L^{-1}\), and 100 mg \(L^{-1}\)) on potato glucose agar. Selected fungi were inoculated onto potato glucose agar (PDA) without dyes (reference samples) and dyed with selected dyes at the indicated concentrations, along with a series of abiotic controls (without fungi) as reference samples to monitor discoloration. White rot fungal growth and dye discoloration were monitored for 49 days by photographing the samples every two days (until the fungi had overgrown the substrate, then every 7 days) using a Nikkon D5600 digital camera. The pre-processing of the captured photographs was done with the program GIMP, which was automated by a developed script. The measurement of growth and discoloration on the processed photos was performed with the program ImageJ. The results obtained in this work are comparable to those available in the literature, which were obtained using the method of measuring the growth diameter and discoloration with a sliding scale. The use of the developed programs and procedures accelerates and facilitates the monitoring of fungal growth and discoloration of the dyes. Limitations in the use of this method, i.e., full automation of the procedure, are related to the problem of image segmentation, i.e., distinguishing the objects of interest from the background, especially in the later stages of incubation due to the growth of mycelia, where thresholding algorithms are not able to segment the image.